Helical Strands Research Articles

Injectable thermo-responsive hydrogel composed of xanthan gum and methylcellulose double networks with shear-thinning property

Injectable hydrogel precursor solution was prepared by physical blend of xanthan gum (XG) and methylcellulose (MC) in aqueous solution. Due to the formation of XG network composed of XG double helical strand structure, XG/MC blend was a high viscous solution with good shear-thinning property at room temperature. When the temperature was changed from 23 to 37°C, thermo-responsive MC network formed, which caused XG/MC blend solution to gelate. The gelation time and storage modulus of the blend can be tuned by XG and/or MC concentrations. Both in vitro and in vivo investigations revealed that the blend solution immediately recovered its high viscosity and rapidly formed hydrogel at body temperature after injection using a syringe. In vivo biocompatibility and biodegradability of the hydrogel were validated by implantation of the hydrogel in rats. In vitro investigation demonstrated that XG/MC blend is a promising injectable hydrogel material for long-term drug delivery.

Multiscale impact of nucleotides and cations on the conformational equilibrium, elasticity and rheology of actin filaments and crosslinked networks.

Cells are able to respond to mechanical forces and deformations. The actin cytoskeleton, a highly dynamic scaffolding structure, plays an important role in cell mechano-sensing. Thus, understanding rheological behaviors of the actin cytoskeleton is critical for delineating mechanical behaviors of cells. The actin cytoskeleton consists of interconnected actin filaments (F-actin) that form via self-assembly of actin monomers. It has been shown that molecular changes of the monomer subunits impact the rigidity of F-actin. However, it remains inconclusive whether or not the molecular changes can propagate to the network level and thus alter the rheological properties of actin networks. Here, we focus on how cation binding and nucleotide state tune the molecular conformation and rigidity of F-actin and a representative rheological behavior of actin networks, strain-stiffening. We employ a multiscale approach by combining established computational techniques: molecular dynamics, normal mode analysis and Brownian dynamics. Our findings indicate that different combinations of nucleotide (ATP, ADP or ADP-Pi) and cation [Formula: see text] or [Formula: see text] at one or multiple sites) binding change the molecular conformation of F-actin by varying inter- and intra-strand interactions which bridge adjacent subunits between and within F-actin helical strands. This is reflected in the rigidity of actin filaments against bending and stretching. We found that differences in extension and bending rigidity of F-actin induced by cation binding to the low-, intermediate- and high-affinity sites vary the strain-stiffening response of actin networks crosslinked by rigid crosslinkers, such as scruin, whereas they minimally impact the strain-stiffening response when compliant crosslinkers, such as filamin A or [Formula: see text]-actinin, are used.

A study on the formation of the nitro radical anion by ornidazole and its significant decrease in a structurally characterized binuclear Cu(II)-complex: impact in biology.

An acetate-bridged binuclear Cu((II)) complex of the antiparasitic drug ornidazole was synthesized and characterized by different techniques. Single crystal X-ray diffraction revealed that the complex had a paddle wheel structure. Enzymatic assay experiments performed under anaerobic conditions on ornidazole and its Cu((II))-complex using xanthine oxidase as a model nitro-reductase showed that complex formation is able to cause a significant decrease in the reduction of the nitro group on the imidazole ring. Reduction products of 5-nitroimidazoles interact with DNA, causing destruction of the double helical structure and strands, leading to the inhibition of protein synthesis. Although not directly coordinated to the metal center, such a decrease in the generation of nitro radical anion through complex formation would result in decreased cytotoxicity of the complex, which could be a disadvantage from the standpoint of drug efficacy. For this reason, other aspects associated with the drug action of 5-nitroimidazoles, such as DNA binding, were studied. Experiments using cyclic voltammetry revealed that the binding of the complex was almost comparable to ornidazole. Bactericidal activity of ornidazole and the complex was studied on two separate bacterial strains, showing that the complex was comparable to ornidazole. Nitro radical anions are known to adversely affect the central nervous system, and this study showed that the Cu((II)) complex has the ability to decrease the generation of NO2˙(-) to an extent that struck the correct balance for beneficial activity, as cytotoxicity due to ornidazole was not affected.

Injectable shear-thinning xanthan gum hydrogel reinforced by mussel-inspired secondary crosslinking

With a xanthan gum double helical strand network and dopamine-mediated crosslinking network, hydrogels possess injectable properties and enhanced mechanical strength.

Type-IV Pilus deformation can explain retraction behavior.

Polymeric filament like type IV Pilus (TFP) can transfer forces in excess of 100 pN during their retraction before stalling, powering surface translocation(twitching). Single TFP level experiments have shown remarkable nonlinearity in the retraction behavior influenced by the external load as well as levels of PilT molecular motor protein. This includes reversal of motion near stall forces when the concentration of the PilT protein is loweblack significantly. In order to explain this behavior, we analyze the coupling of TFP elasticity and interfacial behavior with PilT kinetics. We model retraction as reaction controlled and elongation as transport controlled process. The reaction rates vary with TFP deformation which is modeled as a compound elastic body consisting of multiple helical strands under axial load. Elongation is controlled by monomer transport which suffer entrapment due to excess PilT in the cell periplasm. Our analysis shows excellent agreement with a host of experimental observations and we present a possible biophysical relevance of model parameters through a mechano-chemical stall force map.

Coupling of electric field and bending modulated ballistic transport properties of copper nanowires

Coupling effect of electric field and bending on ballistic transport properties of copper nanowires (NWs) has been studied for the future application in solar cells and flexible displays. Our density function calculations show that when electric field strength V is equal to 0·5 V Å−1, both structures (non-helical strand and helical strand) of CuNW are more stable and exhibit excellent quantum conductivity. Moreover, the helical structures have better stability than the non-helical ones since it owns higher collapse resistant f when V = 1 V Å−1. These results suggested that coupling of electric field and bending can be used to tune transport properties of CuNWs, which may be of help in the design of flexible nanodevices.

Increasing the size of an aromatic helical foldamer cavity by strand intercalation.

The postsynthetic modulation of capsules based on helical aromatic oligoamide foldamers would be a powerful approach for controlling their receptor properties without altering the initial monomer sequences. With the goal of developing a method to increase the size of a cavity within a helix, a single-helical foldamer capsule was synthesized with a wide-diameter central segment that was designed to intercalate with a second shorter helical strand. Despite the formation of stable double-helical homodimers (K(dim)>10(7) M(-1)) by the shorter strand, when it was mixed with the single-helical capsule sequence, a cross-hybridized double helix was formed with K(a)>10(5) M(-1). This strategy makes it possible to direct the formation of double-helical heterodimers. On the basis of solution- and solid-state structural data, this intercalation resulted in an increase in the central-cavity size to give a new interior volume of approximately 150 Å(3).

Increasing the Size of an Aromatic Helical Foldamer Cavity by Strand Intercalation

AbstractThe postsynthetic modulation of capsules based on helical aromatic oligoamide foldamers would be a powerful approach for controlling their receptor properties without altering the initial monomer sequences. With the goal of developing a method to increase the size of a cavity within a helix, a single‐helical foldamer capsule was synthesized with a wide‐diameter central segment that was designed to intercalate with a second shorter helical strand. Despite the formation of stable double‐helical homodimers (Kdim>107 M−1) by the shorter strand, when it was mixed with the single‐helical capsule sequence, a cross‐hybridized double helix was formed with Ka>105 M−1. This strategy makes it possible to direct the formation of double‐helical heterodimers. On the basis of solution‐ and solid‐state structural data, this intercalation resulted in an increase in the central‐cavity size to give a new interior volume of approximately 150 Å3.

Adsorption of small molecules on helical gold nanorods: a relativistic density functional study.

We study the adsorption of a variety of small molecules on helical gold nanorods using relativistic density functional theory. We focus on Au40 which consists of a central linear strand of five gold atoms with seven helical strands of five gold atoms on a coaxial tube. All molecules preferentially adsorb at a single low-coordinated gold atom on the coaxial tube at an end of Au40. In most cases, there is significant charge transfer (CT) between Au40 and the adsorbate, for CO and NO2, there is CT from the Au40 to adsorbate while for all other molecules there is CT from the adsorbate to Au40. Thus, Au40-adsorbate can be described as a donor-accepter complex and we use charge decomposition analysis to better understand the adsorption process. We determine the adsorption energy order to be C5H5N >NO2 > CO > NH3 > CH2=CH2 > CH2=CH-CHO > NO > HC≡CH > H2S > SO2 > HCN > CH3OH > H2C=O > O2 > H2O > CH4 > N2. We find that the Au-C, Au-N, Au-S, and Au-O bonds are surprisingly strong, with clear implications for reactivity enhancement of the adsorbate. The Au-H bond is relatively weak but, for interactions via an H atom that is bonded to a carbon atom (e.g., CH4), we find that there is large charge polarization of the Au-H-C moiety and partial activation of the inert C-H bond. Although the Au-S and Au-O bonds are generally weaker than the Au-C and Au-N bonds, we find that adsorption of H2S or H2O causes greater distortion of Au40 in the binding region. However, the degree of distortion is small and the helical structure is retained, demonstrating the stability of the helical Au40 nanorod under perturbations.

Molecular architectures of new inorganic lamivudine salts, an anti-HIV drug.

One of the currently goals of the crystal engineering is the improvement of pharmaceutical properties of Active Pharmaceutical Ingredients. Herein is discussed the design of new solid forms of the Lamivudine (3TC), one of the most used and marketed anti-HIV drug. The crystalline forms herein presented correspond to inorganic acid salts: Lamivudine hydrobromide (3TCH+-Br-), hydrogen difluoride (3TCH+-F-HF) and nitrate (3TCH+-NO3-). These new salts crystallized in non-centrossymetric space group P21. The halogenated salts (3TCH+-Br-and 3TCH+-F-HF) exhibited isostructural supramolecular assemblies, similar to the anhydrous salt of lamivudine hydrochloride (3TCH+-Cl-) reported by our research group, and whose equilibrium solubility showed an increase when compared with 3TC pharmaceutical form. [1,2] The main feature of the salt crystalline assemblies is related to the supramolecular ordering of the 3TCH+cationic units, by observing the formation of vacancies between them generated in the [100] direction due to the helical symmetry, so, the anions are localized into the interstices of these vacancies, stabilizing the crystalline assemblies. Meanwhile, the 3TCH+NO3-salt showed a different conformational and supramolecular behavior from that observed in the halogenated ones. Here is observed the formation of helical strands along the b axis, which will be engaging by translational symmetry in the horizontal direction in the [10-1] plane. Therefore, they form zigzag molecular planes which will subsequently be architected in parallel with the [10-1] direction. In addition, it was used for this study X-ray powder diffraction (XRDP), vibrational analysis: Infrared (IR) and Raman spectroscopy, and thermal analysis: differential scanning calorimetry (DSC), thermogravimetry (TG) and hot-stage microscopy. Comparison of the structural properties of these salts with some forms already reported (e.g. 3TCH+-Cl-) allows to infer some possible pharmaceutical properties.

Contact effects in spin transport along double-helical molecules

We report on spin transport along double-helical molecular systems by considering various contact configurations and asymmetries between the two helical strands in the regime of completely coherent charge transport. Our results reveal that no spin polarization appears in two-terminal molecular devices when coupled to one-dimensional electrodes. The same holds in the case of finite-width electrodes if there is a \emph{bottleneck} of one single site in the system electrode--molecule--electrode. Then, additional dephasing is necessary to induce spin-filtering effects. In contrast, nonzero spin polarization is found in molecular devices with multiple terminals or with two finite-width electrodes, each of them connected to more than one site of the molecule. Then, the magnitude of spin polarization can be enhanced by increasing the asymmetry between the two strands. We point out that the spin-filtering effects could emerge in double-helical molecular devices at low temperature without dephasing by a proper choice of the electrode number and the connection between the molecule and the electrodes.

Mapping Anillin-Actin Interactions

Cytokinesis requires an assembly of the actomyosin contractile ring (CR) which promotes daughter cell segregation. Assembly of the ring is tightly controlled in space and time. Anilin is a scaffolding protein that is involved in organizing contractile ring components including filamentous actin, myosin and septins. We used Drosophila anillin fragments, purified from E. coli to elucidate how anillin interacts with the actin filament. We show that anillin harbors two actin binding sites (ABS1 and ABS2). Both ABS are required to organize actin filaments into bundles. We used electron microscopy and image analysis to reveal that the anillin ABS1 binds simultaneously to the two sites on the surface of the actin filament and cross-links the two helical strands. It is feasible that anillin may stabilize actin filaments at the site of the CR formation. Interestingly, anillin ABS1 and myosin II have different binding patterns on the F-actin surface, thus the two proteins may not compete for binding to F-actin. To define the contribution of each ABS to cortical localization of anillin during cytokinesis we expressed anillin-GFP fusion fragments in Drosophila S2 cell line. We show that both ABS have to be present in the anillin fragment to follow actin localization at the cortex and cleavage furrow.

Specific Nucleoprotein Residues Affect Influenza Virus Morphology

Influenza virus strains are often pleiomorphic, a characteristic that is largely attributed to specific residues in matrix protein 1 (M1). Although the mechanism by which M1 controls virion morphology has not yet been defined, it is suggested that the M1 interaction with other viral proteins plays an important role. In this study, we rescued recombinant virus WSN-AichiM1 containing the spherical A/WSN/33 (WSN) backbone and the M1 protein from A/Aichi/2/68 (Aichi). Aichi M1 differs from WSN M1 by 7 amino acids but includes those identified to be responsible for filamentous virion formation. Interestingly, Aichi virus produced spherical virions, while WSN-AichiM1 exhibited a long filamentous morphology, as detected by immunofluorescence and electron microscopy. Additional incorporation of Aichi nucleoprotein (NP) but not the hemagglutinin (HA), neuraminidase (NA), or M2 gene to WSN-AichiM1 abrogated filamentous virion formation, suggesting that specific M1-NP interactions affect virion morphology. Further characterization of viruses containing WSN/Aichi chimeric NPs identified residues 214, 217, and 253 of Aichi NP as necessary and sufficient for the formation of spherical virions. NP residues 214 and 217 localize at the minor groove between the two opposite-polarity NP helical strands of viral ribonucleocapsids, and residue 253 also localizes near the surface of the groove. These findings indicate that NP plays a critical role in influenza virus morphology, possibly through its interaction with the M1 layer during virus budding.

Crystal structure of full‐length human collagenase 3 (MMP‐13) with peptides in the active site defines exosites in the catalytic domain

Matrix metalloproteinase (MMP)-13 is one of the mammalian collagenases that play key roles in tissue remodelling and repair and in progression of diseases such as cancer, arthritis, atherosclerosis, and aneurysm. For collagenase to cleave triple helical collagens, the triple helical structure has to be locally unwound before hydrolysis, but this process is not well understood. We report crystal structures of catalytically inactive full-length human MMP-13(E223A) in complex with peptides of 14-26 aa derived from the cleaved prodomain during activation. Peptides are bound to the active site of the enzyme by forming an extended β-strand with Glu(40) or Tyr(46) inserted into the S1' specificity pocket. The structure of the N-terminal part of the peptides is variable and interacts with different parts of the catalytic domain. Those areas are designated substrate-dependent exosites, in that they accommodate different peptide structures, whereas the precise positioning of the substrate backbone is maintained in the active site. These modes of peptide-MMP-13 interactions have led us to propose how triple helical collagen strands fit into the active site cleft of the collagenase.

Dynamic scaffold of chiral binaphthol derivatives with the alkynylplatinum(II) terpyridine moiety

Platinum(II)-containing complexes with inherently chiral binaphthol derivatives display a versatile scaffold between random coils and single-turn helical strands, in which the conformational transition is controlled by the Pt···Pt and π-π interactions of alkynylplatinum(II) terpyridine moiety upon solvent and temperature modulation. The bisignate Cotton effect in the circular dichroism spectra is indicative of the cooperative transformation from random coil state to a compact single-turn M- or P-helix. More importantly, as revealed by the appearance of new UV-vis absorption and emission bands during conformational change, the self-assembly of the platinum(II)-containing complex into a helical structure is assisted by the metal···metal and π-π interactions of the alkynylplatinum(II) terpyridine moieties. The folded structure with stabilization via metal···metal and π-π interactions has been supported by density functional theory calculations, which provide insights into the folded geometry of these kind of metallo-foldamers.

Ethidium bromide binding to DNA cryogels

The interaction of the classical intercalator ethidium bromide (EtBr) with the double helical network strands of DNA cryogels was investigated. The cryogels were prepared starting from aqueous solutions of DNA (about 2000 base pairs long) at −18°C using 1,4-butanediol diglycidyl ether crosslinker under various reaction conditions. In contrast to the solubilization of DNA hydrogels in aqueous EtBr solutions, DNA cryogels remain stable even after complete saturation of their EtBr binding sites. The total binding capacity of the cryogels is 0.6±0.1 EtBr per nucleotide, which is close to the theoretical maximum number of EtBr molecules that can bind to DNA. Even in very dilute solutions (down to 3μM), cryogels remove EtBr from aqueous solutions with an efficiency of 90%. The equilibrium binding constant and the maximum number of EtBr binding sites of the cryogels almost coincide with the reported values for the secondary binding process of EtBr by DNA in aqueous solutions. At low mole ratios of bound EtBr to DNA, the cryogels swell with increasing amount of bound EtBr, most likely caused by the lengthening of DNA due to the intercalated EtBr. The response of DNA cryogels to changes in EtBr concentration between 3 and 300μM also suggests that they can be used to detect DNA binding substrates in aqueous solutions.

Aqueous Self-Assembly of an Electroluminescent Double-Helical Metallopolymer

A new type of water-soluble copper-containing polymer has been synthesized using the technique of subcomponent self-assembly. Copper(I)-directed imine bond formation between triethylene glycol functionalized 1,2-phenylenediamine and 2,9-diformylphenanthroline subcomponents resulted in the formation of a chain in which two conjugated helical ligand strands wrap around a linear array of metal ions. Characterization data from a variety of analytical methods are consistent with our formulation of this material. After purification by dialysis, the polymer was shown to possess several properties of conceptual and practical interest. (1) Individual double-helical strands appear to further aggregate through entanglement of their side chains to form well-defined superstructures such as nanoscale bow ties and macrocycles, which can be imaged on a surface. (2) The material's copper(I) ions underwent reversible electrochemical oxidation in solution, whereas analogous model compounds were observed to decompose upon oxidation: the polymer's greater length appeared to stabilize oxidized states through delocalization or entrapment. (3) Photophysical measurements reveal this material to be photo- and electroluminescent. It has been successfully used for the fabrication of electroluminescent devices and shows a weak emission of white-blue light with CIE coordinates of (0.337, 0.359). This study further demonstrates the utility of the technique of subcomponent self-assembly for the straightforward generation of materials with useful properties.

Conformations of Lower-Size Large Cyclodextrins (DP from 10 to 30) Derived from Conformational Search with Molecular Dynamics and Principal Component Analysis

A new class of compounds, the large-ring cyclodextrins (LR-CDs), attracted attention in recent years, and advances were marked in the study of their physicochemical properties in spite of existing difficulties in their synthesis, isolation and purification. Practical applications were also reported of this new class of compounds. Understanding the mechanism of their action requires knowledge of the macroring conformational dynamics. In view of the difficulties with the experimental examination of the conformations of LR-CDs, computational modeling and simulation methods provide useful tool to gain information about their conformational dynamics, the energetics, and the complex-forming ability. This review summarizes our computational results on the conformations of large-ring cyclodextrins. There are ample evidences to attempt classification (according to their preferred conformation) of the LR-CDs in the range for DP from 10 to 30. Open bend boat-like macrorings are the representative conformations of CD10 to CD13. Two loops situated in mutually perpendicular planes (shaped as number eight) were clearly seen in the average structure of CD14. CD13 and CD14 mark the borderline between lower and higher flexibilities of the CDs macrorings. Two winded single helical strands, apposing each other at different directions, dominate in the structures of the next three LR-CDs (CD15 to CD17), although the CD14-like conformation was also monitored for some of them (CD15, CD17). Two pseudo-cavities with the sizes of α- CD and β-CD were displayed by the average conformations of CD15. These are favorable circumstances for CD14 and CD15 to display better inclusion properties in comparison to the neighbor LR-CDs of higher DP. An expected resemblance with circularized three-turn single helical structure was confirmed for CD21. The CDs from CD22 to CD25 may assume also CD21- and CD26-like conformations during some simulation intervals. Two representative conformations of CD26 (and the CDs in the close vicinity of CD26) are characterized by the presence of two elongated loops with one or two helical turns. A conformation of CD27 resembles the CD21-like circularized three-turn single helical structure. Thus, it is reasonable to assume the possibility for a gradual transition from the CD26 conformations down to the three-turn single helical structure for CD21. The macrorings larger that CD28 most probably can acquire arbitrary shapes with multiple small cavities. All results from our studies are in a support for the domination of representative preferred conformations with a specific shape of the smaller-size LR-CDs (CDn, n=10 to 30) for different ranges of the number of residues. Keywords: Large-ring cyclodextrins, Conformations and macroring conformational dynamics, Molecular dynamics, Principal Component Analysis, glucanotransferases, enzyme-like, cyclohexaicosaose, Crystallization, CYCLODEXTRINS

Conformations of Lower-Size Large Cyclodextrins (DP from 10 to 30) Derived from Conformational Search with Molecular Dynamics and Principal Component Analysis

A new class of compounds, the large-ring cyclodextrins (LR-CDs), attracted attention in recent years, and advances were marked in the study of their physicochemical properties in spite of existing difficulties in their synthesis, isolation and purification. Practical applications were also reported of this new class of compounds. Understanding the mechanism of their action requires knowledge of the macroring conformational dynamics. In view of the difficulties with the experimental examination of the conformations of LR-CDs, computational modeling and simulation methods provide useful tool to gain information about their conformational dynamics, the energetics, and the complex-forming ability. This review summarizes our computational results on the conformations of large-ring cyclodextrins. There are ample evidences to attempt classification (according to their preferred conformation) of the LR-CDs in the range for DP from 10 to 30. Open bend boat-like macrorings are the representative conformations of CD10 to CD13. Two loops situated in mutually perpendicular planes (shaped as number eight) were clearly seen in the average structure of CD14. CD13 and CD14 mark the borderline between lower and higher flexibilities of the CDs macrorings. Two winded single helical strands, apposing each other at different directions, dominate in the structures of the next three LR-CDs (CD15 to CD17), although the CD14-like conformation was also monitored for some of them (CD15, CD17). Two pseudo-cavities with the sizes of α- CD and β-CD were displayed by the average conformations of CD15. These are favorable circumstances for CD14 and CD15 to display better inclusion properties in comparison to the neighbor LR-CDs of higher DP. An expected resemblance with circularized three-turn single helical structure was confirmed for CD21. The CDs from CD22 to CD25 may assume also CD21- and CD26-like conformations during some simulation intervals. Two representative conformations of CD26 (and the CDs in the close vicinity of CD26) are characterized by the presence of two elongated loops with one or two helical turns. A conformation of CD27 resembles the CD21-like circularized three-turn single helical structure. Thus, it is reasonable to assume the possibility for a gradual transition from the CD26 conformations down to the three-turn single helical structure for CD21. The macrorings larger that CD28 most probably can acquire arbitrary shapes with multiple small cavities. All results from our studies are in a support for the domination of representative preferred conformations with a specific shape of the smaller-size LR-CDs (CDn, n=10 to 30) for different ranges of the number of residues. Keywords: Large-ring cyclodextrins, Conformations and macroring conformational dynamics, Molecular dynamics, Principal Component Analysis, glucanotransferases, enzyme-like, cyclohexaicosaose, Crystallization, CYCLODEXTRINS

Two Unique Ligand-Binding Clamps of Rhizopus oryzae Starch Binding Domain for Helical Structure Disruption of Amylose

The N-terminal starch binding domain of Rhizopus oryzae glucoamylase (RoSBD) has a high binding affinity for raw starch. RoSBD has two ligand-binding sites, each containing a ligand-binding clamp: a polyN clamp residing near binding site I is unique in that it is expressed in only three members of carbohydrate binding module family 21 (CBM21) members, and a Y32/F58 clamp located at binding site II is conserved in several CBMs. Here we characterized different roles of these sites in the binding of insoluble and soluble starches using an amylose-iodine complex assay, atomic force microscopy, isothermal titration calorimetry, site-directed mutagenesis, and structural bioinformatics. RoSBD induced the release of iodine from the amylose helical cavity and disrupted the helical structure of amylose type III, thereby significantly diminishing the thickness and length of the amylose type III fibrils. A point mutation in the critical ligand-binding residues of sites I and II, however, reduced both the binding affinity and amylose helix disruption. This is the first molecular model for structure disruption of the amylose helix by a non-hydrolytic CBM21 member. RoSBD apparently twists the helical amylose strands apart to expose more ligand surface for further SBD binding. Repeating the process triggers the relaxation and unwinding of amylose helices to generate thinner and shorter amylose fibrils, which are more susceptible to hydrolysis by glucoamylase. This model aids in understanding the natural roles of CBMs in protein-glycan interactions and contributes to potential molecular engineering of CBMs.