Parental Template Research Articles

A smart processing of silicon oxynitride ceramic powders with variable morphology controlled by hard template assistance

Spherical and rod-like Si2N2O ceramic powders were successfully prepared using a hard template strategy to meet different application background. The mesoporous silica spheres and rod-like silica (SBA-15) particles were selected as hard templates and also served as reactants. Highly active mesoporous silica is reacted through a combination of sucrose-nano-casting and carbothermal reduction nitridation (CRN) to successfully synthesize spherical and rod-like powders. Temperature and holding time of calcination are found to be significant factors for the formation of pure and well-crystallized powders. Insufficient temperature and holding time cause an incomplete reaction between silica, carbon and nitrogen, and also lead to the formation of amorphous phase. In the processing, sucrose was used as carbon source to incorporate evenly into mesopores of templates to assist CRN reaction. Big surface areas and high porosity of mesopores in SiO2 provide an additional driving force to decrease the formation temperature of Si2N2O phase to 1280°C. As-synthesized powders inherit same morphology as their parental mesoporous templates, which indicate that two mesoporous templates play an important role in guiding the growth of ceramic particles. In the research, we develop a smart processing for synthesis of oxynitride powders with variable morphology controlled by template.

Pore structure effects on the kinetics of methanol oxidation over nanocast mesoporous perovskites

Mesoporous LaMnO3 perovskite catalysts with high surface area were synthesized by using the recently developed hard templating method designated as “nanocasting”. Ordered mesoporous silica designated as SBA-15 was used as the hard template. It was found that the surface area of the nanocast perovskites can be tuned (80–190 m2/g) by varying the aging temperature of the SBA-15 template. Nanocast LaMnO3 catalysts showed high conversion efficiencies for the total oxidation of methanol under steady state conditions, the one with the highest value of surface area being the best catalysts, as expected. Kinetic studies were performed for all of the synthesized catalysts. Rate constants were found to vary in accordance with the specific surface area of the nanocast catalyst which depends on the aging temperature of the parent template. From the rate constants obtained from experimental conversions at various space velocities (19500 to 78200 h−1), values of activation energy and pre-exponential factor for the three nanocast LaMnO3 catalysts were determined by the linear regression of the Arrhenius plot. It is observed that the activation energy for all the catalysts remain constant irrespective of the variation in specific surface area. Further, a linear relationship was found to exist between the pre-exponential factor and specific surface areas of the catalysts indicating that the rates per unit surface area remains the same for all the catalysts.

ICRP Publication 131: Stem Cell Biology with Respect to Carcinogenesis Aspects of Radiological Protection.

This report provides a review of stem cells/progenitor cells and their responses to ionising radiation in relation to issues relevant to stochastic effects of radiation that form a major part of the International Commission on Radiological Protection's system of radiological protection. Current information on stem cell characteristics, maintenance and renewal, evolution with age, location in stem cell 'niches', and radiosensitivity to acute and protracted exposures is presented in a series of substantial reviews as annexes concerning haematopoietic tissue, mammary gland, thyroid, digestive tract, lung, skin, and bone. This foundation of knowledge of stem cells is used in the main text of the report to provide a biological insight into issues such as the linear-no-threshold (LNT) model, cancer risk among tissues, dose-rate effects, and changes in the risk of radiation carcinogenesis by age at exposure and attained age. Knowledge of the biology and associated radiation biology of stem cells and progenitor cells is more developed in tissues that renew fairly rapidly, such as haematopoietic tissue, intestinal mucosa, and epidermis, although all the tissues considered here possess stem cell populations. Important features of stem cell maintenance, renewal, and response are the microenvironmental signals operating in the niche residence, for which a well-defined spatial location has been identified in some tissues. The identity of the target cell for carcinogenesis continues to point to the more primitive stem cell population that is mostly quiescent, and hence able to accumulate the protracted sequence of mutations necessary to result in malignancy. In addition, there is some potential for daughter progenitor cells to be target cells in particular cases, such as in haematopoietic tissue and in skin. Several biological processes could contribute to protecting stem cells from mutation accumulation: (a) accurate DNA repair; (b) rapidly induced death of injured stem cells; (c) retention of the DNA parental template strand during divisions in some tissue systems, so that mutations are passed to the daughter differentiating cells and not retained in the parental cell; and (d) stem cell competition, whereby undamaged stem cells outcompete damaged stem cells for residence in the niche. DNA repair mainly occurs within a few days of irradiation, while stem cell competition requires weeks or many months depending on the tissue type. The aforementioned processes may contribute to the differences in carcinogenic radiation risk values between tissues, and may help to explain why a rapidly replicating tissue such as small intestine is less prone to such risk. The processes also provide a mechanistic insight relevant to the LNT model, and the relative and absolute risk models. The radiobiological knowledge also provides a scientific insight into discussions of the dose and dose-rate effectiveness factor currently used in radiological protection guidelines. In addition, the biological information contributes potential reasons for the age-dependent sensitivity to radiation carcinogenesis, including the effects of in-utero exposure.

Teen Fathers: Implications for School Counselors

Researchers studying teen parenting have mainly concentrated on teen mothers while neglecting and negatively portraying teen fathers. Stereotypes confronting teen include them being uncaring, absent, disinterested, unable to meet responsibilities, and unwilling participants in the lives of their children (Frewin, Tuffin, & Rouch, 2007). Within several studies, researchers have only included the teen mother's perspectives of the father and of her baby and have relied on the mother's opinions regarding the father's role and involvement (Reeves, 2007; Bunting & McAuley, 2004; Amin & Ahmed, 2004; Robbers, 2009). The behavior of the teen father is better understood within his internal and external environmental factors. Many times teen are not allowed input in what happens with their children because they are treated with hostility from the child's mother's family (Fagan, Bernd, & Whiteman, 2007). When the teen mother's family disapproves of him and wants her to distance herself from the baby's father, her family is frequently discouraging an otherwise interested father from having a relationship with his child and with the mother of his baby (Wiemann, Agurcia, Rickert, Berenson, & Volk, 2006). These are very difficult and trying times in a teen father's life. Adolescence is a challenging and confusing developmental period where the adolescent experiences profound social, physical, and psychological changes. This is a time of pubertal changes, the evolution of abstract thinking, and increase in self-consciousness and self-concept (Frewin et al., 2007). It is also a period in the adolescent's life when he/she is establishing his/her independence from family, developing close bonds with friends, and becoming romantically involved. Becoming a father at this time means the teen must grow up quickly, and this period of time becomes a turning point in his life. The teen father can be propelled into adult roles and responsibilities when he is transitioned to fatherhood. Typically, teen mothers and are limited in their educational attainment and are more restricted in their employment opportunities (Sipsma, Biello, Cole-Lewis, & Kershaw, 2010). The children of teen parents are often raised in lower-income homes and are at a greater risk for neglect and abuse than children of older parents (Sipsma et al., 2010). Sipsma et al. (2010) conducted a study of 1,496 teen and found that of adolescent were 1.8 times more likely to become adolescent than were sons of older fathers (p. 517). Only recently have researchers begun to study this group. As a result of this new body of literature, specific indicators have been identified. For example, children without their father in their lives scored lower on measures of trust, self-esteem, socialization, and achievement (Amin & Ahmed, 2004). These children are also at a greater risk of early sexual experimentation, drug abuse, poor school performance, delinquency, and truancy. Frequently, this leads to more problems in their adult life including replication of the single parent template (Parker, 2011). Conversely, teen father's involvement with his child's mother and child increases the mother's sense of confidence in nurturing skills and raises the teen father's self-esteem (Amin & Ahmed, 2004). Review of Literature Historically, teen have been thought of as outcasts and surrounded by negative stereotyping since few marry the mother of their children (Amin & Ahmed, 2004). Frewin et al. (2007) conducted a study of 12 teen aged 18 and younger and in high school. Each teen father was well aware of his responsibilities as a father and was far from being disinterested. None of these teen intentionally became fathers, and they would not recommend this life course (Frewin et al., 2007). These teen were no longer able to participate in their former activities with their peers. …

Hierarchically built gold nanoparticle supercluster arrays as charge storage centers for enhancing the performance of flash memory devices.

Flash memory devices with high-performance levels exhibiting high charge storage capacity, good charge retention, and high write/erase speeds with lower operating voltages are widely in demand. In this direction, we demonstrate hierarchical self-assembly of gold nanoparticles based on block copolymer templates as a promising route to engineer nanoparticle assemblies with high nanoparticle densities for application in nanocrystal flash memories. The hierarchical self-assembly process allows systematic multiplication of nanoparticle densities with minimal increase in footprint, thereby increasing the charge storage density without an increase in operating voltage. The protocol involves creation of a parent template composed of gold nanoclusters that guides the self-assembly of diblock copolymer reverse micelles which in turn directs electrostatic assembly of gold nanoparticles resulting in a three-level hierarchical system. Capacitance-voltage (C-V) measurements of the hierarchical nanopatterns with a metal-insulator-semiconductor capacitor configuration reveal promising enhancement in memory window as compared to nonhierarchical nanoparticle controls. Capacitance-time (C-t) measurements show that over half the stored charges were retained when extrapolated to 10 years. The fabrication route can be readily extended to programmed density multiplication of features made of other potential charge storage materials such as platinum, palladium, or hybrid metal/metal oxides for next generation, solution-processable flash memory devices.

Elucidation of the DNA End-Replication Problem in Saccharomyces cerevisiae

The model for telomere shortening at each replication cycle is currently incomplete, and the exact contribution of the telomeric 3' overhang to the shortening rate remains unclear. Here, we demonstrate key steps of the mechanism of telomere replication in Saccharomyces cerevisiae. By following the dynamics of telomeres during replicationat near-nucleotide resolution, we find that the leading-strand synthesis generates blunt-end intermediates before being 5'-resected and filled in. Importantly, the shortening rate is set by positioning the last Okazaki fragments at the very ends of the chromosome. Thus, telomeres shorten in direct proportion to the 3' overhang lengths of 5-10 nucleotides that are present in parental templates. Furthermore, the telomeric protein Cdc13 coordinates leading- and lagging-strand syntheses. Taken together, our data unravel a precise choreography of telomere replication elucidating the DNA end-replication problem and provide a framework to understand the control of the cell proliferation potential.

Hierarchical micro-mesoporous carbons by direct replication of bimodal aluminosilicate templates

The objective of this work was to produce carbons with controllable bimodal porosity in the micro-mesopore range. Hierarchical micro-mesoporous carbons were prepared by direct replication, using bimodal Y zeolite core/MCM-48 silica shell aluminosilicates as templates. Different variables of the chemical vapor deposition (CVD) process were studied in order to achieve a suitable infiltration of both meso and micropores of the templates. Thus, one-step infiltration with acetylene and also two-step infiltration with acetylene and propylene were performed to further investigate the effect of the precursor and CVD steps duration. One-step acetylene CVD gave the best results since the obtained carbons exhibited high specific surfaces areas of 1000–1323m2/g, and their X-ray diffraction and transmission electron microscopy analysis revealed that they faithfully replicated the hierarchical core–shell structure of the parent template. When propylene was used as carbon source a better replication of the mesoporous shell was achieved, but as a counterpoint, the replication of the microporous core failed.

A mutant screening method by critical annealing temperature-PCR for site-directed mutagenesis

BackgroundDistinguishing desired mutants from parental templates and undesired mutants is a problem not well solved in Quikchange™ mutagenesis. Although Dpn I digestion can eliminate methylated parental (WT) DNA, the efficiency is not satisfying due to the existence of hemi-methylated DNA in the PCR products, which is resistant to Dpn I. The present study designed a novel critical annealing temperature (Tc)-PCR to replace Dpn I digestion for more perfect mutant distinguishing, in which part-overlapping primers containing mutation(s) were used to reduce initial concentration of template DNA in mutagenic PCR. A Tc-PCR with the same mutagenic primers was performed without Dpn I digestion. The Tc for each pair of the primers was identified by gradient PCR. The relationship between PCR-identified Tc and Tm of the primers was analyzed and modeled with correlation and regression.ResultsGradient PCR identified a Tc for each of 14 tested mutagenic primers, which could discriminate mismatched parental molecules and undesired mutants from desired mutants. The PCR-identified Tc was correlated to the primer’s Tm (r = 0.804, P<0.0001). Thus, in practical applications, the Tc can be easily calculated with a regression equation, Tc = 48.81 + 0.253*Tm.ConclusionsThe new protocol introduced a novel Tc-PCR method for mutant screening which can more efficiently and accurately select against parental molecules and undesired mutations in mutagenic sequence segments.

Discovering non-random segregation of sister chromatids: the naïve treatment of a premature discovery.

The discovery of non-random chromosome segregation (Figure 1) is discussed from the perspective of what was known in 1965 and 1966. The distinction between daughter, parent, or grandparent strands of DNA was developed in a bacterial system and led to the discovery that multiple copies of DNA elements of bacteria are not distributed randomly with respect to the age of the template strand. Experiments with higher eukaryotic cells demonstrated that during mitosis Mendel’s laws were violated; and the initial serendipitous choice of eukaryotic cell system led to the striking example of non-random segregation of parent and grandparent DNA template strands in primary cultures of cells derived from mouse embryos. Attempts to extrapolate these findings to established tissue culture lines demonstrated that the property could be lost. Experiments using plant root tips demonstrated that the phenomenon exists in plants and that it was, at some level, under genetic control. Despite publication in major journals and symposia (Lark et al., 1966, 1967; Lark, 1967, 1969a,b,c) the potential implications of these findings were ignored for several decades. Here we explore possible reasons for the pre-maturity (Stent, 1972) of this discovery.

DNA template strand sequencing of single-cells maps genomic rearrangements at high resolution

DNA rearrangements such as sister chromatid exchanges (SCEs) are sensitive indicators of genomic stress and instability, but they are typically masked by single-cell sequencing techniques. We developed Strand-seq to independently sequence parental DNA template strands from single cells, making it possible to map SCEs at orders-of-magnitude greater resolution than was previously possible. On average, murine embryonic stem (mES) cells exhibit eight SCEs, which are detected at a resolution of up to 23 bp. Strikingly, Strand-seq of 62 single mES cells predicts that the mm 9 mouse reference genome assembly contains at least 17 incorrectly oriented segments totaling nearly 1% of the genome. These misoriented contigs and fragments have persisted through several iterations of the mouse reference genome and have been difficult to detect using conventional sequencing techniques. The ability to map SCE events at high resolution and fine-tune reference genomes by Strand-seq dramatically expands the scope of single-cell sequencing.

Mutational showers during carcinogenesis

Mutational showers during carcinogenesis

Pax6 Controls the Expression of Critical Genes Involved in Pancreatic α Cell Differentiation and Function*

The paired box homeodomain Pax6 is crucial for endocrine cell development and function and plays an essential role in glucose homeostasis. Indeed, mutations of Pax6 are associated with diabetic phenotype. Importantly, homozygous mutant mice for Pax6 are characterized by markedly decreased β and δ cells and absent α cells. To better understand the critical role that Pax6 exerts in glucagon-producing cells, we developed a model of primary rat α cells. To study the transcriptional network of Pax6 in adult and differentiated α cells, we generated Pax6-deficient primary rat α cells and glucagon-producing cells, using either specific siRNA or cells expressing constitutively a dominant-negative form of Pax6. In primary rat α cells, we confirm that Pax6 controls the transcription of the Proglucagon and processing enzyme PC2 genes and identify three new target genes coding for MafB, cMaf, and NeuroD1/Beta2, which are all critical for Glucagon gene transcription and α cell differentiation. Furthermore, we demonstrate that Pax6 directly binds and activates the promoter region of the three genes through specific binding sites and that constitutive expression of a dominant-negative form of Pax6 in glucagon-producing cells (InR1G9) inhibits the activities of the promoters. Finally our results suggest that the critical role of Pax6 action on α cell differentiation is independent of those of Arx and Foxa2, two transcription factors that are necessary for α cell development. We conclude that Pax6 is critical for α cell function and differentiation through the transcriptional control of key genes involved in glucagon gene transcription, proglucagon processing, and α cell differentiation.

Chromosome orientation fluorescence in situ hybridization to study sister chromatid segregation in vivo

Previously, assays for sister chromatid segregation patterns relied on incorporation of 5-bromo-2'-deoxyuridine (BrdU) and indirect methods to infer segregation patterns after two cell divisions. In this study, we describe a method to differentially label sister chromatids of mouse cells and to directly assay sister chromatid segregation patterns after one cell division in vitro and in vivo by adaptation of the well-established CO-FISH technique. BrdU is incorporated into newly formed DNA strands, which are then subjected to photolysis and exonuclease digestion to create single-stranded sister chromatids containing parental template DNA only. Such single-stranded sister chromatids are differentially labeled using unidirectional probes to major satellite sequences coupled to fluorescent markers. Differentially labeled sister chromatids in postmitotic cells are visualized using fluorescence microscopy, and sister chromatid segregation patterns can be directly assayed after one cell division. This procedure requires 4 d for in vivo mouse tissues and 2 d for in vitro-cultured cells.

On the Relevance of the Met-turn Methionine in Metzincins

The metzincins are a clan of metallopeptidases consisting of families that share a series of structural elements. Among them is the Met-turn, a tight 1,4-turn found directly below the zinc-binding site, which is structurally and spatially conserved and invariantly shows a methionine at position 3 in all metzincins identified. The reason for this conservation has been a matter of debate since its discovery. We have studied this structural element in Methanosarcina acetivorans ulilysin, the structural prototype of the pappalysin family, by generating 10 mutants that replaced methionine with proteogenic amino acids. We compared recombinant overexpression yields, autolytic and tryptic activation, proteolytic activity, thermal stability, and three-dimensional structure with those of the wild type. All forms were soluble and could be purified, although with varying yields, and three variants underwent autolysis, could be activated by trypsin, and displayed significant proteolytic activity. All variants were analyzed for the thermal stability of their zymogens. None of the mutants analyzed proved more stable or active than the wild type. Both bulky and small side chains, as well as hydrophilic ones, showed diminished thermal stability. Two mutants, leucine and cysteine, crystallized and showed three-dimensional structures that were indistinguishable from the wild type. These studies reveal that the Met-turn acts as a plug that snugly inserts laterally into a core structure created by the protein segment engaged in zinc binding and thus contributes to its structural integrity, which is indispensable for function. Replacement of the methionine with residues that deviate in size, side-chain conformation, and chemical properties impairs the plug-core interaction and prejudices molecular stability and activity.

Defining the modular protein intereactions that coordinate recruitment of DNA polymerase alpha to initiate SV40 DNA replication

SV40 DNA replication, a simple but powerful model system, can be reconstituted with purified recombinant proteins in vitro, providing an opportunity to identify at the atomic level how a small number of eukaryotic proteins interact to initiate replication at a defined origin. Indeed four recombinant proteins suffice to initiate replication. Previous work from our labs and others suggests that origin melting by the viral helicase T antigen (Tag) leads to a transient ternary complex of Tag, RPA, and ssDNA. This complex dissociates as more ssDNA emerges from the helicase, generating RPA‐ssDNA parental template. Tag associated with DNA polymerase alpha‐primase (pol‐prim) is proposed to then remodel the bound RPA into a weaker binding mode, allowing pol‐prim to gain access to the exposed ssDNA and begin primer synthesis (EMBO J 25, 5516; NSMB 12, 332). This working model predicts that specific contacts of pol‐prim with the helicase domain of Tag are required to initiate replication. To further test the model, we determined the solution structure of the Tag‐interacting domain of pol‐prim regulatory subunit p68, characterized the binding surfaces of p68 and Tag, and will present evidence that interaction between these surfaces is needed for initiation in a reconstituted system. A model in which multiple defined protein interactions coordinate initiation of replication will be presented. (NIH GM52948 to EF and GM65484 to WJC)

Structural and functional consequences of the Milano mutation (R173C) in human apolipoprotein A-I

Carriers of the apolipoprotein A-I(Milano) (apoA-I(M)) variant, R173C, have reduced levels of plasma HDL but no increase in cardiovascular disease. Despite intensive study, it is not clear whether the removal of the arginine or the introduction of the cysteine is responsible for this altered functionality. We investigated this question using two engineered variations of the apoA-I(M) mutation: R173S apoA-I, similar to apoA-I(M) but incapable of forming a disulfide bond, and R173K apoA-I, a conservative mutation. Characterization of the lipid-free proteins showed that the order of stability was wild type approximately R173K>R173S>R173C. Compared with wild-type apoA-I, apoA-I(M) had a lower affinity for lipids, while R173S apoA-I displayed intermediate affinity. The in vivo effects of the apoA-I variants were measured by injecting apoA-I-expressing adeno-associated virus into apoA-I-null mice. Mice that expressed the R173S variant again showed an intermediate phenotype. Thus, both the loss of the arginine and its replacement by a cysteine contribute to the altered properties of apoA-I(M). The arginine is potentially involved in an intrahelical salt bridge with E169 that is disrupted by the loss of the positively charged arginine and repelled by the cysteine, destabilizing the helix bundle domain in the apoA-I molecule and modifying its lipid binding characteristics.

Golden Gate Shuffling: A One-Pot DNA Shuffling Method Based on Type IIs Restriction Enzymes

We have developed a protocol to assemble in one step and one tube at least nine separate DNA fragments together into an acceptor vector, with 90% of recombinant clones obtained containing the desired construct. This protocol is based on the use of type IIs restriction enzymes and is performed by simply subjecting a mix of 10 undigested input plasmids (nine insert plasmids and the acceptor vector) to a restriction-ligation and transforming the resulting mix in competent cells. The efficiency of this protocol allows generating libraries of recombinant genes by combining in one reaction several fragment sets prepared from different parental templates. As an example, we have applied this strategy for shuffling of trypsinogen from three parental templates (bovine cationic trypsinogen, bovine anionic trypsinogen and human cationic trypsinogen) each divided in 9 separate modules. We show that one round of shuffling using the 27 trypsinogen entry plasmids can easily produce the 19,683 different possible combinations in one single restriction-ligation and that expression screening of a subset of the library allows identification of variants that can lead to higher expression levels of trypsin activity. This protocol, that we call ‘Golden Gate shuffling’, is robust, simple and efficient, can be performed with templates that have no homology, and can be combined with other shuffling protocols in order to introduce any variation in any part of a given gene.

Cep76, a Centrosomal Protein that Specifically Restrains Centriole Reduplication

Centrosomes duplicate only once per cell cycle, but the controls that govern this process are largely unknown. We have identified Cep76, a centriolar protein that interacts with CP110. Cep76 is expressed at low levels in G1 and is induced in S and G2 phase, during which point centrioles have already commenced duplication. Interestingly, depletion of Cep76 drives the accumulation of centriolar intermediates in certain types of cancer cells. Enforced Cep76 expression specifically inhibits centriole amplification in cells undergoing multiple rounds of duplication without preventing the formation of extra procentrioles from a parental template. Furthermore, elevated levels of Cep76 do not affect normal centriole duplication. Thus, Cep76 helps limit duplication to once per cell cycle. Our findings also point to mechanistic differences between normal duplication and aberrant centriole amplification, as well as distinctions between diverse modes of amplification.

Nucleobase-Templated Polymerization: Copying the Chain Length and Polydispersity of Living Polymers into Conjugated Polymers

Conjugated polymers synthesized by step polymerization mechanisms typically suffer from poor molecular weight control and broad molecular weight distributions. We report a new method which uses nucleobase recognition to read out and efficiently copy the controlled chain length and narrow molecular weight distribution of a polymer template generated by living polymerization, into a daughter conjugated polymer. Aligning nucleobase-containing monomers on their complementary parent template using hydrogen-bonding interactions, and subsequently carrying out a Sonogashira polymerization, leads to the templated synthesis of a conjugated polymer. Remarkably, this daughter strand is found to possess a narrow molecular weight distribution and a chain length nearly equivalent to that of the parent template. On the other hand, nontemplated polymerization or polymerization with the incorrect template generates a short conjugated oligomer with a significantly broader molecular weight distribution. Hence, nucleobase-templated polymerization is a useful tool in polymer synthesis, in this case allowing the use of a large number of polymers generated by living methods, such as anionic polymerization, controlled radical polymerizations (NMP, ATRP, and RAFT) and other mechanisms to program the structure, length, and molecular weight distribution of polymers normally generated by step polymerization methods and significantly enhance their properties.

Homology modeling and flex-ligand docking studies on the guinea pig β2 adrenoceptor: structural and experimental similarities/ differences with the human β2

The trachea of a guinea pig is widely used in drug development assays focused on the treatment of pulmonary diseases. Some of these drugs relax the airways by binding to the guinea pig beta(2)-adrenoceptor (Gbeta(2)AR). In this work, the amino acid sequence of the Gbeta(2)AR was searched to carry out homology modeling, using the Swiss-Model server, with the human beta(2)AR as the parent template. The Gbeta(2)AR 3-D structure was structurally and energetically optimized in vacuo using NAMD 2.6 program. The refined 3-D model obtained was used for further study. Molecular docking simulations were performed by testing a set of well-known beta(2)AR ligands using the AutoDock 3.0.5 program. The results show that the homology model of Gbeta(2)AR has a 3-D structure very similar to the crystal structure of recently studied human beta(2)AR. This was also corroborated by identity (94.23%), Ramachandran map, and docking results. The theoretical simulation showed that the ligands bind at sites that are similar to those reported for the human beta(2)AR. The R-enantiomer ligands showed correlation with in vitro data. We have obtained a Gbeta(2)AR 3-D model which can be used to carry out computational screening as a complementary tool during the drug design and experimental tests under guinea pig models.