Addition Of Maltose Research Articles

The Discovery, Molecular Cloning, and Characterization of Dextransucrase LmDexA and Its Active Truncated Mutant from Leuconostoc mesenteroides NN710.

Dextransucrases play a crucial role in the production of dextran from economical sucrose; therefore, there is a pressing demand to explore novel dextransucrases with better performance. This study characterized a dextransucrase enzyme, LmDexA, which was identified from the Leuconostoc mesenteroides NN710. This bacterium was isolated from the soil of growing dragon fruit in Guangxi province, China. We successfully constructed six different N-terminal truncated variants through sequential analysis. Additionally, a truncated variant, ΔN190LmDexA, was constructed by removing the 190 amino acids fragment from the N-terminal. This truncated variant was then successfully expressed heterologously in Escherichia coli and purified. The purified ΔN190LmDexA demonstrated optimal hydrolysis activity at a pH of 5.6 and a temperature of 30 °C. Its maximum specific activity was measured to be 126.13 U/mg, with a Km of 13.7 mM. Results demonstrated a significant improvement in the heterologous expression level and total enzyme activity of ΔN190LmDexA. ΔN190LmDexA exhibited both hydrolytic and transsaccharolytic enzymatic activities. When sucrose was used as the substrate, it primarily produced high-molecular-weight dextran (>400 kDa). However, upon the addition of maltose as a receptor, it resulted in the production of a significant amount of oligosaccharides. Our results can provide valuable information for enhancing the characteristics of recombinant dextransucrase and potentially converting sucrose into high-value-added dextran and oligosaccharides.

Effect and mechanism of signal peptide and maltose on recombinant type III collagen production in Pichia pastoris.

Recombinant type III collagen plays an important role in cosmetics, wound healing, and tissue engineering. Thus, increasing its production is necessary. After an initial increase in output by modifying the signal peptide, we showed that adding 1% maltose directly to the medium increased the yield and reduced the degradation of recombinant type III collagen. We initially verified that Pichia pastoris GS115 can metabolize and utilize maltose. Interestingly, maltose metabolism-associated proteins in Pichia pastoris GS115 have not yet been identified. RNA sequencing and transmission electron microscopy were performed to clarify the specific mechanism of maltose influence. The results showed that maltose significantly improved the metabolism of methanol, thiamine, riboflavin, arginine, and proline. After adding maltose, the cell microstructures tended more toward the normal. Adding maltose also contributed to yeast homeostasis and methanol tolerance. Finally, adding maltose resulted in the downregulation of aspartic protease YPS1 and a decrease in yeast mortality, thereby slowing down recombinant type III collagen degradation. KEY POINTS: • Co-feeding of maltose improves recombinant type III collagen production. • Maltose incorporation enhances methanol metabolism and antioxidant capacity. • Maltose addition contributes to Pichia pastoris GS115 homeostasis.

Differences in organic nitrogen transformation during chicken manure composting with the addition of different disaccharides

The effect of different carbon sources on nitrogen (N) transformation and N loss through nitrogenous gas volatilization during composting of manure is not clear. Disaccharides had moderate degradation stability compared to monosaccharides and polysaccharides. Therefore, we investigated the effect of adding sucrose (nonreducing sugar) and maltose (reducing sugar) as carbon sources on volatile N loss and hydrolysable organic nitrogen (HON) transformation. HON is composed of bioavailable organic nitrogen (BON) and hydrolysable unknown nitrogen (HUN). Three laboratory-scale experimental groups were conducted with control (CK), 5 % sucrose (SS), and 5 % maltose (MS) addition. Our findings indicated that, while excluding leaching and surface runoff, adding sucrose and maltose decreased the N loss through gas volatilization by 15.78 % and 9.77 %, respectively. The addition of maltose significantly increased the BON content (P < 0.05), which was 6.35 % higher than in CK. The addition of sucrose led to an increase in HUN content (P < 0.05), which was 22.89 % higher than that in CK. In addition, the core microbial communities associated with HON changed after the addition of disaccharides. The transformation of the HON fractions was facilitated by the succession of microbial communities. Ultimately, variation partition analysis (VPA) and structural equation modeling (SEM) verified that the core microbial communities were the major contributors to promoting HON transformation. In summary, adding disaccharides could promote the different transformations of organic nitrogen (ON) and reduce the volatilization of nitrogenous gases by changing the succession of the core microbial communities during composting. This study provided theoretical and technical support for reducing volatile N loss and promoting ON fraction sequestration during composting. Furthermore, the effect of carbon source addition on the nitrogen cycle was also explored.

Production of pigments by Monascus ruber CCT0302 in culture media containing maltose as substrate

The aim of this study was to show how maltose production residues can be used to obtain natural pigments by Monascus ruber CCT 3802 in solid and submerged cultures. The microbial growth and the colour and heat stability characteristics of the pigments produced in both solid and submerged media, with different maltose syrup concentrations, were determined. The results showed that the addition of maltose provided significant increases in the velocity of microbial growth and production of red pigments. The highest radial growth velocity of Monascus ruber (0.1053 mm h−1) was obtained when cultivated in a medium containing 5 g L−1 of maltose syrup, corresponding to a 71.7% increase in growth as compared to the growth velocity in the control medium. Using submerged fermentation, the culture medium containing 10 g L−1 of maltose syrup provided the greatest concentrations of red pigments (14.54 AU510nm g−1 dry biomass) with an intense dark red colour, showing that Monascus ruber CCT 3802 had the capacity to assimilate the substrate and produce pigments. The red pigments produced in the cultures showed good heat stability with activation energies of 13.735 Kcal mol−1.

Purification and characterization of lipase produced by indigenously isolated bacteria

Bacteria including Bacillus species often produce extracellular enzymes to degrade substances such as proteins, lipids, and starch. Glycerol and long-chain fatty acids are hydrolyzed by lipases (triacylglycerol acylhydrolases, EC 3.1.1.3) to generate esters. Bacterial strains were isolated from rotten fruits and vegetables and cultured at 20 to 50 0C with different types of substrates (Olive oil, Mustard oil and Tributryne). Extracellular enzymes produces from bacteria with different physical parameter and also using different substrates. Only two strains, strain 1 and strain 2 show results when provided substrate Olive oil and Mustard oil at pH 7 and at temperature 300C but Tributryne show result at pH 9 and at temperature 400C. Addition of maltose and fructose increased the lipase activity to 28.53U/ mL and 30.17U/mL respectively. The activity enhance to 50.83U/mL by the addition of yeast extract as nitrogen source. Addition of 60% ammonium sulfate results in maximum precipitation with activity 59.46 U/mL. The results concluded that isolated bacterial strains are good producer of lipase enzyme. The purified enzyme could be a good candidate for various industrial applications. Keywords: Ammonium sulfate precipitation; Bacillus species; Lipase activity; Rotten fruits; Tributryne agar Plate http://dx.doi.org/10.19045/bspab.2020.90268

Analysis of Structural and Functional Differences of Glucans Produced by the Natively Released Dextransucrase of Liquorilactobacillus hordei TMW 1.1822

The properties of the glucopolymer dextran are versatile and linked to its molecular size, structure, branching, and secondary structure. However, suited strategies to control and exploit the variable structures of dextrans are scarce. The aim of this study was to delineate structural and functional differences of dextrans, which were produced in buffers at different conditions using the native dextransucrase released by Liquorilactobacillus (L.) hordei TMW 1.1822. Rheological measurements revealed that dextran produced at pH 4.0 (MW = 1.1 * 108 Da) exhibited the properties of a viscoelastic fluid up to concentrations of 10% (w/v). By contrast, dextran produced at pH 5.5 (MW = 1.86 * 108 Da) was gel-forming already at 7.5% (w/v). As both dextrans exhibited comparable molecular structures, the molecular weight primarily influenced their rheological properties. The addition of maltose to the production assays caused the formation of the trisaccharide panose instead of dextran. Moreover, pre-cultures of L. hordei TMW 1.1822 grown without sucrose were substantial for recovery of higher dextran yields, since the cells stored the constitutively expressed dextransucrase intracellularly, until sucrose became available. These findings can be exploited for the controlled recovery of functionally diverse dextrans and oligosaccharides by the use of one dextransucrase type.

Statistical optimization of bacterial cellulose production by Leifsonia soli and its physico-chemical characterization

Bacterial cellulose has multiple applications in various industries such as food, biomedical, textile due to its uniqueness of being a better bio-compatible coating agent, binding material, etc. In this study, optimization of the culture medium for producing BC from Leifsonia soli was carried out by selecting different parameters. Five significant factors such as maltose, pH, incubation days, soy whey and calcium chloride were estimated through ANOVA based response surface methodology. Maximum cellulose production (5.97 g/L) was obtained where maltose 1 % (w/v) supplemented with 0.8 % (v/v) soy whey and calcium chloride 0.8 % (w/v) at pH 6.5 for 7 days of incubation. In addition, assurance of cellulose production from bacteria was done by using High-performance liquid chromatography analysis. Further, the structure and purity of obtained cellulose were examined by SEM and elemental analysis where it was observed that the sample holds the value of carbon 44.1 ± 0.20 % and hydrogen 6.2 ± 0.3 %, respectively. This study concludes that the addition of maltose and soy whey could be used as carbon, nitrogen sources and calcium chloride was used as an additive for the bacterial cellulose production compared to the Hestrin Schramm medium. In addition, the calculated water holding capacity of the sample was found to be 73 %.

Sugar Protectants Improve the Thermotolerance and Biocontrol Efficacy of the Biocontrol Yeast, Candida oleophila.

A variety of sugar compounds have been used as additives to protect various biocontrol yeasts from adverse environmental stresses. However, studies on maltose and lactose as sugar protectants are limited, and their protective effect is not clear. In the present study, exposure of the biocontrol yeast Candida oleophila cells to 45°C for 10 min, while immersed in either 5 or 10% (w/v) maltose or lactose, provided a significant protective effect. The addition of maltose and lactose significantly enhanced enzyme activity and gene expression of catalase, thioredoxin reductase, and glutathione reductase, relative to cells that have been immersed in sterile distilled water (controls) exposed to 45°C. In addition, C. oleophila cells suspended in maltose and lactose solutions also exhibited higher viability and ATP levels, relative to control cells. Notably, the biocontrol efficacy of C. oleophila against postharvest diseases of apple fruit was maintained after the yeast was exposed to the high temperature treatment while immersed in maltose and lactose solutions. These results demonstrate the potential of maltose and lactose as sugar protectants for biocontrol agent against heat stress.

Evaluation of maltose binding to proteinase K: Insights from spectroscopic and computational approach

The change in structure, function of proteinase K in the presence of maltose was studied using spectroscopic and computational techniques. UV–Vis spectroscopy results reveal with the addition of maltose, the peaks of proteinase K didn't show any shifts. The intrinsic fluorescence intensity was decreased regularly with rising the ligand concentration. These results suggest that the quenching mode is dynamic quenching. Far-UV circular dichroism (CD) studies showed a low decrease in the β-sheet, β-turn and the large increase in the α-helix. The activity of proteinase K was increased in the presence of maltose. Thus, maltose is an activator for proteinase K. Molecular docking results show a negative value for the Gibbs free energy. On the other hand, the thermal stability of proteinase K was investigated in the presence of maltose over the temperature range (298–353) K. Obtained data indicate the thermal stability of proteinase K will be reduced when the concentration of maltose increase. These results are confirmed by the molecular dynamic simulation technique.

Maltose-mediated long-term stabilization of freeze- and spray- dried forms of bovine and porcine hemoglobin

Slaughterhouse blood represents a valuable source of hemoglobin, which can be used in the production of heme-iron based supplements for the prevention/treatment of iron-deficiency anemia. In order to obtain a stable solid-state formulation, the effect of maltose addition (30 %) on the stability and storage of bovine and porcine hemoglobin in powders obtained by spray and freeze-drying (without maltose: Hb; with maltose: HbM) were investigated. Differential scanning calorimetry of spray- and freeze-dried powders indicated satisfying quality of the formulation prepared with maltose on dissolving back into solution. After two-year storage at room temperature (20?5?C) in solid forms, protected from moisture and light, rehydrated spray- and freeze-dried HbM were red, while Hb were brown. Dynamic light scattering showed the presence of native hemoglobin monomers in rehydrated spray- and freeze-dried HbM, but their agglomerates in Hb samples. UV?Vis spectrophotometry confirmed an absence of significant hemoglobin denaturation and methemoglobin formation in HbM freeze-dried powders. In spray-dried HbM, an increased level of methemoglobin was detected. The results confirmed the stabilizing effect of maltose, and suggested its use in the production of long-term stable solid-state formulations of hemoglobin, along with drying processes optimization.

Regeneration of highland papaya (Vasconcellea pubescens) from anther culture.

Premise of the Study Vasconcellea pubescens is an important Caricaceae species cultivated in several countries of South America. The objective of this study was to investigate different media compositions and plant growth regulators to induce plant regeneration.MethodsAnthers were cultured in Murashige and Skoog medium with varying concentrations of naphthalene acetic acid (NAA) and 2,4‐dichlorophenoxyacetic acid (2,4‐D) plus a cytokinin (N‐(2‐chloro‐4‐pyridyl)‐N′‐phenylurea). The effect of the basal medium supplemented with auxins and cytokinins on shoot regeneration from the induced calli was also evaluated. Addition of maltose to the basal medium was also tested.ResultsThe combination of 0.54 μM NAA and 22.66 μM 2,4‐D induced the highest rate of calli formation. Regeneration via organogenesis was obtained in Murashige and Skoog and Woody Plant Medium supplemented with maltose and containing 8.88 μM 6‐benzylaminopurine, 5.71 μM indoleacetic acid, and 2.28 μM zeatin.DiscussionThe plant regeneration protocol reported here permits the development of haploid and double haploid plants that can be useful for propagation purposes, allow a better molecular understanding of the species, and facilitate the production of new cultivars.

A Quantum Dot-Protein Bioconjugate That Provides for Extracellular Control of Intracellular Drug Release.

The ability to control the intracellular release of drug cargos from nanobioconjugate delivery scaffolds is critical for the successful implementation of nanoparticle (NP)-mediated drug delivery. This is particularly true for hard NP carriers such as semiconductor quantum dots (QDs) and gold NPs. Here, we report the development of a QD-based multicomponent drug release system that, when delivered to the cytosol of mammalian cells, is triggered to release its drug cargo by the simple addition of a competitive ligand to the extracellular medium. The ensemble construct consists of the central QD scaffold that is decorated with a fixed number of maltose binding proteins (MBPs). The MBP binding site is loaded with dye or drug conjugates of the maltose analogue beta-cyclodextrin (βCD) to yield a QD-MBP-βCD ensemble conjugate. The fidelity of conjugate assembly is monitored by Förster resonance energy transfer (FRET) from the QD donor to the dye/drug acceptor. Microplate-based FRET assays demonstrated that the βCD conjugate was released from the MBP binding pocket by maltose addition with an affinity that matched native MBP-maltose binding interactions. In COS-1 cells, the microinjected assembled conjugates remained stably intact in the cytosol until the addition of maltose to the extracellular medium, which underwent facilitated uptake into the cell. Live cell FRET-based confocal microscopy imaging captured the kinetics of realtime release of the βCD ligand as a function of extracellular maltose concentration. Our results demonstrate the utility of the self-assembled QD-MBP-βCD system to facilitate intracellular drug release that is triggered extracellularly through the simple addition of a well-tolerated nutrient and is not dependent on the use of light, magnetic field, ultrasound, or other traditional methods of stimulated drug release. We expect this extracellularly triggered drug release modality to be useful for the in vitro characterization of new drug candidates intended for systemic delivery/actuation and potentially for on-demand drug release in vivo.

Solid-state cultivation of recombinant Aspergillus nidulans to co-produce xylanase, arabinofuranosidase, and xylooligosaccharides from soybean fibre

Abstract Solid-state cultivations of genetically modified strains of Aspergillus nidulans A773, using soybean fibre as substrate, were carried out to produce xylanase and arabinofuranosidase, and these enzymes were subsequently used to obtain xylooligosaccharides using the same agro-residue. First, the best fungi cultivation conditions (moisture content, pH, temperature and addition of maltose) were optimized one-by-one for obtain the crude enzyme extracts. Subsequently, the application of xylanase on soybean fibre to obtain xylooligosaccharides was optimized by central composite design, defining best enzyme concentration and reaction temperature. The best condition obtained (50 °C and 117 U g−1 of soybean fibre) was used to evaluate the co-production of xylooligosaccharides by the addition of different concentrations of arabinofuranosidase. The highest yield of xylooligosaccharides obtained was 28% (mass fraction of xylan), showing final concentrations (in mg g−1 arabino-xylan) of 138.36 xylobiose (X2), 96.96 xylotriose (X3), and 53.04 xylotetraose (X4), in 9 h enzymatic reactions. The conversion of arabino-xylans into different xylooligosaccharides suggests the potential to use recombinant A. nidulans A773 enzymes to obtain prebiotics using a sugar-rich, low-cost soybean residue.

Disaccharides: Influence on Volatiles and Phenolics of Sour Cherry Juice.

The food industry is continuously developing ingredients, processing methods and packaging materials to improve the quality of fruit products. The aim of this work was to study the effect of sugars, a common ingredient in the food industry, on phenolics and volatiles of sour cherry juice. Sucrose, trehalose and maltose chemical isomers were chosen for this investigation. All sugars influenced the evaluated parameters. Samples with maltose addition had lower, while samples with sucrose and trehalose addition had higher anthocyanin content than the control sample. Generally, trehalose had a higher positive effect on volatiles with the desired flavor note.

STRAIN IMPROVEMENT THROUGH MUTAGENESIS AND OPTIMIZATION OF PROTEASE PRODUCTION BY ASPERGILLUS TERREUS CJS-127 USING JATROPHA SEED CAKE AS SUBSTRATE

Jatropha curcas seedcake (JSC), a byproduct of the biodiesel industry was utilized for the production of protease. To enhance the protease production, the parent strain of Aspergillus terreus CJS-127 subjected to UV (15, 30, 60, 90, 120 and 150 min) and chemical mutagenesis by using ethyl methanesulphonate (EMS-125, 250 and 500 mg). Two mutant strains designated as UV-6 and EMS-5 selected for optimization of protease production using JSC medium by submerged fermentation. Under the optimized conditions of pH 7.0, temperature 30°C, incubation period 72 h, inoculum 105/ml spores, 150 rpm agitation, JSC at 2% level, the maximum protease production was 172.32 and 163.57 U/ml for EMS-5 and UV-6 mutant strains respectively. The addition of maltose (2%) was found to enhance the protease production in the mutant strains. The protease activity increased by 2.30 and 2.41 folds for UV 6 and EMS 5 mutant strains after optimization of cultural conditions.

Phenolics and antioxidant activity of freeze-dried sour cherry puree with addition of disaccharides

This study was carried out to determine the influence of disaccharides on phenolics and antioxidant activity of freeze-dried sour cherry puree. The freeze-dried sour cherry purees were prepared without and with addition of maltose, sucrose or trehalose in amounts of 5, 10 or 20%. Addition of maltose and trehalose had a positive effect on preservation of anthocyanins, especially on cyanidin-3-glucosylrutinosid. Positive effect of sugars was the most pronounced for cyanidin-3-glucosylrutinosid and the least for cyanidin-3-glucoside. The highest content of individual anthocyanins except cyanidin-3-glucoside was measured in sample with addition of 20% of maltose. Results of antioxidant activity (AA) measured with ABTS and FRAP followed the same trends with a positive correlation of r = 0.824. Antioxidant activity measured with ABTS also showed the positive correlation with total phenolics, flavonoids and with sum of individual anthocyanins (r = 0.745, 0.709 and 0.814, respectively). The AA measured with all three methods (DPPH, ABTS, and FRAP) showed that sample with addition of 20% of maltose had the highest AA, 65.46, 28.45, 62.24 mg GAE/100 g, respectively.

Room Temperature Consolidation of a Porous Poly(lactic-co-glycolic acid) Matrix by the Addition of Maltose to the Water-in-Oil Emulsion.

In composite materials made of polymer matrices and micro-nano dispersed compartments, the morphology of the dispersed phase can strongly affect several features of the final material, including stability, loading efficiency, and kinetic release of the embedded molecules. Such a polymer matrix composite can be obtained through the consolidation of the continuous polymer phase of a water-in-oil (W/O) emulsion. Here, we show that the morphology of the dispersed phase in a poly(lactic-co-glycolic acid, PLGA) matrix can be optimized by combining an effective mild temperature drying process with the addition of maltose as a densifying compound for the water phase of the emulsion. The influence of this addition on final stability and consequent optimal pore distribution was theoretically and experimentally confirmed. Samples were analyzed in terms of morphology on dried flat substrates and in terms of rheology and interfacial tension at the liquid state. While an increase of interfacial tension was found following the addition of maltose, the lower difference in density between the two emulsion phases coming from the addition of maltose allowed us to estimate a reduced creaming tendency confirmed by the experimental observations. Rheological measurements also confirmed an improved elastic behavior for the maltose-containing emulsion.

Maltose Effects on Barley Malt Diastatic Power Enzyme Activity and Thermostability at High Isothermal Mashing Temperatures: II. α-Amylase

This study was conducted to determine if maltose, the primary product of starch degradation during mashing, would affect the activity of or increase the thermostability of barley malt α-amylase activity at high temperatures used in mashing and temperatures above those normally used in mashing. Malts of the two-row cultivar Harrington and the six-row cultivar Morex were mashed for 2 h with maltose concentrations of 0–500 mM at temperatures from 63 to 78°C. Worts were sampled every 30 min for 120 min and α-amylase activities determined utilizing the Megazyme Ceralpha assay. Mannitol, a polyhydric alcohol, was used for comparison. Polyhydric alcohols are known to enhance enzyme thermostability. At 63°C both cultivars had relatively thermostable α-amylase without the addition of maltose or mannitol. However, Morex, and to a lesser extent Harrington, α-amylase activity was significantly elevated by high levels of either maltose or mannitol, indicating a stimulatory effect on activity in which thermostability was apparently not involved. At 73 and 78°C increasing concentrations of maltose conferred considerable and highly significant (LSD analysis, P < 0.0001) thermal protection of α-amylase in both cultivars. For example, at 30 min of mashing at 73°C, maltose concentrations of 400 and 500 mM resulted in α-amylase activity in Harrington of 227 and 252% and in Morex 349 and 314%, respectively, of the 0 mM maltose activity. At 60 min of mashing at 73°C, concentrations of 400 and 500 mM maltose resulted in α-amylase activities of Harrington of 290 and 431% and Morex of 489 and 501%, respectively, of the 0 mM maltose activity. High mannitol incubations at higher temperatures such as at 73°C rendered lesser α-amylase thermal protection than maltose; however, it was also considerable and highly significant (P < 0.0001) for both cultivars (e.g., 30 min incubation at 73°C, with 400 and 500 mM maltose, respectively, α-amylase activities of Harrington were 163 and 174% and Morex were 188 and 260% of the 0 mM maltose activity). These data suggest that the production of maltose, as could be expected in high-gravity mashes, significantly increases the activity and thermostability of barley malt α-amylase.

Production and Thermal Characterization of an Alkaline Pectin Lyase from Penicillium notatum

Abstract The present study was aimed to investigate the potential of Penicillium notatum for the production of pectin lyase under solid state culture using wheat bran as substrate. Different process parameters were optimized using completely randomized design for enhanced production of the pectin lyase. P. notatum showed maximum production (1875 U/gds) of pectin lyase with substrate amount 15 g/250 ml, moisture level 60%, pH 6, incubation period 120 h at 30°C. Pectin lyase activity was further improved with the addition of maltose and ammonium sulphate as carbon and nitrogen additives (1%), respectively. Partial purification of enzyme was carried out by ammonium sulphate precipitation at 80% saturation level. The P. notatum pectin lyase showed maximal activity at 65°C and pH 8. K m and V max values were 0.29% and 0.487 µmol/min, respectively. Energy of activation was found to be 5.33 kJ/mol. A detailed kinetic study of thermal inactivation was carried out. The results showed that pectin lyase exhibited resistance against thermal unfolding. Effect of various metals on pectin lyase activity was also investigated. All the metals showed inhibitory effect on the enzyme activity. The present investigation revealed that pectin lyase isolated from P. notatum is thermally stable and alkaline in nature.

Competitive Interactions of Ligands and Macromolecular Crowders with Maltose Binding Protein

Cellular signaling involves a cascade of recognition events occurring in a complex environment with high concentrations of proteins, polysaccharides, and other macromolecules. The influence of macromolecular crowders on protein binding affinity through hard-core repulsion is well studied, and possible contributions of protein-crowder soft attraction have been implicated recently. Here we present direct evidence for weak association of maltose binding protein (MBP) with a polysaccharide crowder Ficoll, and that this association effectively competes with the binding of the natural ligand, maltose. Titration data over wide ranges of maltose and Ficoll concentrations fit well with a three-state competitive binding model. Broadening of MBP 1H­15N TROSY spectra by the addition of Ficoll indicates weak protein-crowder association, and subsequent recovery of sharp NMR peaks upon addition of maltose indicates that the interactions of the crowder and the ligand with MBP are competitive. We hypothesize that, in the Escherichia coli periplasm, the competitive interactions of polysaccharides and maltose with MBP could allow MBP to shuttle between the peptidoglycan attached to the outer membrane and the ATP-binding cassette transporter in the inner membrane.