1
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Meirovitch E, Liang Z, Freed JH. Phenyl-Ring Dynamics in Amyloid Fibrils and Proteins: The Microscopic-Order-Macroscopic-Disorder Perspective. J Phys Chem B 2018; 122:8675-8684. [PMID: 30141954 DOI: 10.1021/acs.jpcb.8b06330] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have developed the microscopic-order-macroscopic-disorder (MOMD) approach for studying internal mobility in polycrystalline proteins with 2H lineshape analysis. The motion itself is expressed by a diffusion tensor, R, the local spatial restraints by a potential, u, and the "local geometry" by the relative orientation of the model-related and nuclear magnetic resonance-related tensors. Here, we apply MOMD to phenyl-ring dynamics in several Αβ40-amyloid-fibrils, and the villin headpiece subdomain (HP36). Because the available data are limited in extent and sensitivity, we adjust u and R in the relevant parameter ranges, fixing the "local geometry" in accordance with standard stereochemistry. This yields a physically well-defined and consistent picture of phenyl-ring dynamics, enabling comparison between different systems. In the temperature range of 278-308 K, u has a strength of (1.7-1.8) kT and a rhombicity of (2.4-2.6) kT, and R has components of 5.0 × 102 ≤ R⊥ ≤ 2.0 × 103 s-1 and 6.3 × 105 ≤ R∥ ≤ 2.0 × 106 s-1. At 278 K, fibril hydration increases the axiality of both u and R; HP36 hydration has a similar effect at 295 K, reducing R⊥ considerably. The D23N mutation slows down the motion of the probe; Aβ40 polymorphism affects both this motion and the related local potential. The present study identifies the impact of various factors on phenyl-ring mobility in amyloid fibrils and globular proteins; the difference between the two protein forms is considerable. The distinctive impact of hydration on phenyl-ring motion and previously studied methyl-group motion is also examined. The 2H lineshapes considered here were analyzed previously with various multi-simple-mode (MSM) models, where several simple motional modes are combined. The MOMD and MSM interpretations differ in essence.
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Affiliation(s)
- Eva Meirovitch
- The Mina and Everard Goodman Faculty of Life Sciences , Bar-Ilan University , Ramat-Gan 5290002 , Israel
| | - Zhichun Liang
- Baker Laboratory of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853-1301 , United States
| | - Jack H Freed
- Baker Laboratory of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853-1301 , United States
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2
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Immobilized cutinases: Preparation, solvent tolerance and thermal stability. Enzyme Microb Technol 2018; 116:33-40. [DOI: 10.1016/j.enzmictec.2018.05.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 05/07/2018] [Accepted: 05/11/2018] [Indexed: 12/22/2022]
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3
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Developing a High-Temperature Solvent-Free System for Efficient Biocatalysis of Octyl Ferulate. Catalysts 2018. [DOI: 10.3390/catal8080338] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Ferulic acid esters have been suggested as a group of natural chemicals that have the function of sunscreen. The study aimed to utilize an environmentally-friendly enzymatic method through the esterification of ferulic acid with octanol, producing octyl ferulate. The Box-Behnken experimental design for response surface methodology (RSM) was performed to determine the synthesis effects of variables, including enzyme amount (1000–2000 propyl laurate units (PLU)), reaction temperature (70–90 °C), and stir speed (50–150 rpm) on the molar conversion of octyl ferulate. According to the joint test, both the enzyme amount and reaction temperature had great impacts on the molar conversion. An RSM-developed second-order polynomial equation further showed a data-fitting ability. Using ridge max analysis, the optimal parameters of the biocatalyzed reaction were: 72 h reaction time, 92.2 °C reaction temperature, 1831 PLU enzyme amount, and 92.4 rpm stir speed, respectively. Finally, the molar conversion of octyl ferulate under optimum conditions was verified to be 93.2 ± 1.5%. In conclusion, it has been suggested that a high yield of octyl ferulate should be synthesized under elevated temperature conditions with a commercial immobilized lipase. Our findings could broaden the utilization of the lipase and provide a biocatalytic approach, instead of the chemical method, for ferulic acid ester synthesis.
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4
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Kamal MZ, Yedavalli P, Deshmukh MV, Rao NM. Lipase in aqueous-polar organic solvents: activity, structure, and stability. Protein Sci 2013; 22:904-15. [PMID: 23625694 DOI: 10.1002/pro.2271] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 04/17/2013] [Accepted: 04/19/2013] [Indexed: 11/06/2022]
Abstract
Studying alterations in biophysical and biochemical behavior of enzymes in the presence of organic solvents and the underlying cause(s) has important implications in biotechnology. We investigated the effects of aqueous solutions of polar organic solvents on ester hydrolytic activity, structure and stability of a lipase. Relative activity of the lipase monotonically decreased with increasing concentration of acetone, acetonitrile, and DMF but increased at lower concentrations (upto ~20% v/v) of dimethylsulfoxide, isopropanol, and methanol. None of the organic solvents caused any appreciable structural change as evident from circular dichorism and NMR studies, thus do not support any significant role of enzyme denaturation in activity change. Change in 2D [15N, 1H]-HSQC chemical shifts suggested that all the organic solvents preferentially localize to a hydrophobic patch in the active-site vicinity and no chemical shift perturbation was observed for residues present in protein's core. This suggests that activity alteration might be directly linked to change in active site environment only. All organic solvents decreased the apparent binding of substrate to the enzyme (increased Km ); however significantly enhanced the kcat . Melting temperature (Tm ) of lipase, measured by circular dichroism and differential scanning calorimetry, altered in all solvents, albeit to a variable extent. Interestingly, although the effect of all organic solvents on various properties on lipase is qualitatively similar, our study suggest that magnitudes of effects do not appear to follow bulk solvent properties like polarity and the solvent effects are apparently dictated by specific and local interactions of solvent molecule(s) with the protein.
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Affiliation(s)
- Md Zahid Kamal
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, India
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5
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Borowiecki P, Milner-Krawczyk M, Plenkiewicz J. Chemoenzymatic synthesis and biological evaluation of enantiomerically enriched 1-(β-hydroxypropyl)imidazolium- and triazolium-based ionic liquids. Beilstein J Org Chem 2013; 9:516-25. [PMID: 23616792 PMCID: PMC3628848 DOI: 10.3762/bjoc.9.56] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 02/15/2013] [Indexed: 01/22/2023] Open
Abstract
Racemic 1-(β-hydroxypropyl)azoles were prepared by solvent-free direct regioselective ring opening of 1,2-propylene oxide with imidazole or 1,2,4-triazole. Lipase-catalyzed transesterification of alcohols with vinyl acetate resulted in kinetic enantiomers resolution. Separated (S)-enantiomers of (+)-1-(1H-imidazol-1-yl)propan-2-ol and (+)-1-(1H-1,2,4-triazol-1-yl)propan-2-ol were quaternized with alkyl bromides or iodides, yielding novel optically active ionic liquids. Racemic salts were tested against a wide range of microorganisms.
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Affiliation(s)
- Paweł Borowiecki
- Warsaw University of Technology, Faculty of Chemistry, Noakowskiego St. 3, 00-664 Warsaw, Poland
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6
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Gallou F, Seeger-Weibel M, Chassagne P. Development of a Robust and Sustainable Process for Nucleoside Formation. Org Process Res Dev 2013. [DOI: 10.1021/op300335d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fabrice Gallou
- Novartis Pharma AG, Chemical
and Analytical Development, CH-4002 Basel, Switzerland
| | | | - Pierre Chassagne
- Novartis Pharma AG, Chemical
and Analytical Development, CH-4002 Basel, Switzerland
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7
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Zheng J, Xu L, Liu Y, Zhang X, Yan Y. Lipase-coated K2SO4 micro-crystals: preparation, characterization, and application in biodiesel production using various oil feedstocks. BIORESOURCE TECHNOLOGY 2012; 110:224-231. [PMID: 22330591 DOI: 10.1016/j.biortech.2012.01.088] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 01/14/2012] [Accepted: 01/17/2012] [Indexed: 05/31/2023]
Abstract
This study investigated the preparation and characteristics of protein-coated microcrystals (PCMCs) from Pseudomonas cepacia lipase (PS) and K(2)SO(4), and their application in biodiesel synthesis, via single factorial experiments and response surface methodology (RSM), the optimized PCMC-PS exhibited high activity and stability; the optimal temperature was 60°C (which gave 99.83% conversion), although fairly high activity was exhibited after incubation at different temperatures (25-70°C). The organic solvents stability of the PCMC-PS was improved, and it significantly reduced ethanol toxicity. Circular dichroism (CD) analysis revealed the correlation between the conformation and the enzyme activity. The morphology of the PCMC-PS was also confirmed via scanning electron microscopy (SEM). When catalyzed by PCMC-PS, above 83% biodiesel yield was obtained for most of the seven oils tested. The PCMC-PS (washed with hexane) activity remained relatively stable after eight batch reactions, with only a 15.73% reduction in the conversion (from 99.02% to 83.29%).
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Affiliation(s)
- Jingjing Zheng
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China
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8
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Ma X, Sun C, Huang J, Boutis GS. Thermal hysteresis in the backbone and side-chain dynamics of the elastin mimetic peptide [VPGVG]3 revealed by 2H NMR. J Phys Chem B 2012; 116:555-64. [PMID: 22142235 PMCID: PMC3257400 DOI: 10.1021/jp208966k] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report on experimental measurements of the backbone and side-chain dynamics of the elastin mimetic peptide [VPGVG](3) by (2)H NMR echo spectroscopy and 2D T(1)-T(2) correlation relaxometry. The T(1) and T(2) relaxation times of the Gly α-deuterons and Val α-, β-, and γ-deuterons of a hydrated sample reveal a thermal hysteresis when the temperature is raised from -10 to 45 °C and then subsequently cooled back to -10 °C. In addition, near 30 °C we observe a reduction in the slope of the T(1)(T) and T(2)(T) heating curves, indicating a structural change that appears to be correlated well to the known inverse temperature transition of this peptide. The thermal dependence of the correlation times of the Gly α-deuterons are well fit by an Arrhenius Law, from which we measured E(act) = (20.0 ± 3.1) kJ/mol when the sample is heated and E(act) = (10.9 ± 2.8) kJ/mol when cooled. Molecular dynamics simulations support the notion that the measured activation energy is determined largely by the extent of localized water, which is observed to decrease with increasing temperature from approximately 25 to 42 °C.
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Affiliation(s)
- Xiang Ma
- Department of Physics, Brooklyn College of the City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210
| | - Cheng Sun
- Department of Physics, Brooklyn College of the City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210
| | - Jiaxin Huang
- Department of Physics, Brooklyn College of the City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210
| | - Gregory S. Boutis
- Department of Physics, Brooklyn College of the City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210
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9
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Verma PK, Rakshit S, Mitra RK, Pal SK. Role of hydration on the functionality of a proteolytic enzyme α-chymotrypsin under crowded environment. Biochimie 2011; 93:1424-33. [DOI: 10.1016/j.biochi.2011.04.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 04/20/2011] [Indexed: 11/28/2022]
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10
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Paravidino M, Sorgedrager MJ, Orru RVA, Hanefeld U. Activity and enantioselectivity of the hydroxynitrile lyase MeHNL in dry organic solvents. Chemistry 2010; 16:7596-604. [PMID: 20486110 PMCID: PMC2970910 DOI: 10.1002/chem.201000487] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Indexed: 11/23/2022]
Abstract
Water concentration affects both the enantioselectivity and activity of enzymes in dry organic media. Its influence has been investigated using the hydrocyanation of benzaldehyde catalyzed by hydroxynitrile lyase cross-linked enzyme aggregate (MeHNL-CLEA) as a model reaction. The enzyme displayed higher enantioselectivity at higher water concentration, thus suggesting a positive effect of enzyme flexibility on selectivity. The activity increased on reducing the solvent water content, but drastic dehydration of the enzyme resulted in a reversible loss of activity.
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Affiliation(s)
- Monica Paravidino
- Gebouw voor Scheikunde, Afdeling Biotechnologie, Technische Universiteit Delft, Julianalaan 136, 2628 BL Delft, The Netherlands
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11
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Crilly S, Magner E. Reversible conformational change of cytochrome c at a modified gold electrode in methanol. Phys Chem Chem Phys 2010; 12:10093-7. [DOI: 10.1039/c0cp00350f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Hudson EP, Eppler RK, Beaudoin JM, Dordick JS, Reimer JA, Clark DS. Active-site motions and polarity enhance catalytic turnover of hydrated subtilisin dissolved in organic solvents. J Am Chem Soc 2009; 131:4294-300. [PMID: 19317505 DOI: 10.1021/ja806996q] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The enzyme subtilisin Carlsberg was surfactant-solubilized into two organic solvents, isooctane and tetrahydrofuran, and hydrated through stepwise changes in the thermodynamic water activity, a(w). The apparent turnover number k(cat)(app) in these systems ranged from 0.2 to 80 s(-1) and increased 11-fold in isooctane and up to 50-fold in tetrahydrofuran with increasing a(w). (19)F NMR relaxation experiments employing an active-site inhibitor were used to assess the dependence of active-site motions on a(w). The rates of NMR-derived fast (k > 10(7) s(-1)) and slow (k < 10(4) s(-1)) active-site motions increased in both solvents upon hydration, but only the slow motions correlated with k(cat). The (19)F chemical shift was a sensitive probe of the local electronic environment and provided an empirical measure of the active-site dielectric constant epsilon(as), which increased with hydration to epsilon(as) approximately 13 in each solvent. In both solvents, the transition state free energy data and epsilon(as) followed Kirkwood's model for the continuum solvation of a dipole, indicating that water also enhanced catalysis by altering the active-site's electronic environment and increasing its polarity to better stabilize the transition state. These results reveal that favorable dynamic and electrostatic effects both contribute to accelerated catalysis by solubilized subtilisin Carlsberg upon hydration in organic solvents.
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Affiliation(s)
- Elton P Hudson
- Department of Chemical Engineering, University of California, Berkeley, California 94720, USA
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13
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Synthesis of fatty acid esters and diacylglycerols at elevated temperatures by alkalithermophilic lipases from Thermosyntropha lipolytica. J Ind Microbiol Biotechnol 2009; 36:1281-7. [DOI: 10.1007/s10295-009-0610-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Accepted: 06/16/2009] [Indexed: 10/20/2022]
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14
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Lambert C, Pourplanche C, Larreta-Garde V. Comparison of Macromolecular and Molecular Effects of Cosolvents on the Catalytic Behaviour of Soybean Lipoxygenase-1. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.3109/10242429709003609] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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15
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Rariy RV, Klibanov AM. On the Relationship Between Enzymatic Enantioselectivity in Organic Solvents and Enzyme Flexibility. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.3109/10242420009015259] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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16
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Biocatalyst activity in nonaqueous environments correlates with centisecond-range protein motions. Proc Natl Acad Sci U S A 2008; 105:15672-7. [PMID: 18840689 DOI: 10.1073/pnas.0804566105] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recent studies exploring the relationship between enzymatic catalysis and protein dynamics in the aqueous phase have yielded evidence that dynamics and enzyme activity are strongly correlated. Given that protein dynamics are significantly attenuated in organic solvents and that proteins exhibit a wide range of motions depending on the specific solvent environment, the nonaqueous milieu provides a unique opportunity to examine the role of protein dynamics in enzyme activity. Variable-temperature kinetic measurements, X-band electron spin resonance spectroscopy, (1)H NMR relaxation, and (19)F NMR spectroscopy experiments were performed on subtilisin Carlsberg colyophilized with several inorganic salts and suspended in organic solvents. The results indicate that salt activation induces a greater degree of transition-state flexibility, reflected by a more positive DeltaDeltaS(dagger), for the more active biocatalyst preparations in organic solvents. In contrast, DeltaDeltaH(dagger) was negligible regardless of salt type or salt content. Electron spin resonance spectroscopy and (1)H NMR relaxation measurements, including spin-lattice relaxation, spin-lattice relaxation in the rotating frame, and longitudinal magnetization exchange, revealed that the enzyme's turnover number (k(cat)) was strongly correlated with protein motions in the centisecond time regime, weakly correlated with protein motions in the millisecond regime, and uncorrelated with protein motions on the piconanosecond timescale. In addition, (19)F chemical shift measurements and hyperfine tensor measurements of biocatalyst formulations inhibited with 4-fluorobenzenesulfonyl fluoride and 4-ethoxyfluorophosphinyl-oxy-TEMPO, respectively, suggest that enzyme activation was only weakly affected by changes in active-site polarity.
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18
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Castillo B, Solá RJ, Ferrer A, Barletta G, Griebenow K. Effect of PEG modification on subtilisin Carlsberg activity, enantioselectivity, and structural dynamics in 1,4-dioxane. Biotechnol Bioeng 2008; 99:9-17. [PMID: 17546684 DOI: 10.1002/bit.21510] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The employment of enzymes as catalysts within organic media has traditionally been hampered by the reduced enzymatic activities when compared to catalysis in aqueous solution. Although several complementary hypotheses have provided mechanistic insights into the causes of diminished activity, further development of biocatalysts would greatly benefit from effective chemical strategies (e.g., PEGylation) to ameliorate this event. Herein we explore the effects of altering the solvent composition from aqueous buffer to 1,4-dioxane on structural, dynamical, and catalytic properties of the model enzyme subtilisin Carlsberg (SBc). Furthermore, we also investigate the effects of dissolving the enzyme in 1,4-dioxane through chemical modification with poly(ethylene)-glycol (PEG, M(W) = 20 kDa) on these enzyme properties. In 1,4-dioxane a 10(4)-fold decrease in the enzyme's catalytic activity was observed for the hydrolysis reaction of vinyl butyrate with D(2)O and a 50% decrease in enzyme structural dynamics as evidenced by reduced amide H/D exchange kinetics occurred. Attaching increasing amounts of PEG to the enzyme reversed some of the activity loss. Evaluation of the structural dynamic behavior of the PEGylated enzyme within the organic solvent revealed an increase in structural dynamics at increased PEGylation. Correlation analysis between the catalytic and structural dynamic parameters revealed that the enzyme's catalytic activity and enantioselectivity depended on the changes in protein structural dynamics within 1,4-dioxane. These results demonstrate the importance of protein structural dynamics towards regulating the catalytic behavior of enzymes within organic media.
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Affiliation(s)
- Betzaida Castillo
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, P.O. Box 23346, San Juan 00931-3346, Puerto Rico
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19
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Castillo B, Méndez J, Al-Azzam W, Barletta G, Griebenow K. On the relationship between the activity and structure of PEG-alpha-chymotrypsin conjugates in organic solvents. Biotechnol Bioeng 2006; 94:565-74. [PMID: 16496401 DOI: 10.1002/bit.20863] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Enzymes are attractive catalysts for the production of optically active compounds in organic solvents. However, their often low catalytic activity in such applications hampers their practical use. To overcome this, we investigated the effectiveness of the covalent modification of alpha-chymotrypsin with methoxy poly(ethylene glycol) (PEG) with a Mw of 5,000 to enhance its activity. The model transesterification reaction between sec-phenethyl alcohol and vinyl butyrate in various neat dry organic solvents and at a controlled water activity of 0.008 in two solvents was employed to measure the effect of PEGylation on activity and enantioselectivity. Synthesis conditions were varied to obtain various conjugates with average molar ratios of PEG-to-chymotrypsin ranging from ca. 1 to 7. While the enantioselectivity increased only modestly from ca. 4.4 to 6.1 when averaging results in all solvents, PEG was very efficient in increasing the activity of alpha-chymotrypsin up to more than 400-fold compared to that of the powder lyophilized from buffer alone. The activity increase was more pronounced in apolar than in polar organic solvents and also depended on the amount of PEG bound to the enzyme. For example, the activity of the modified enzyme towards the most reactive "S" enantiomer in octane increased 440-fold but increasing the molar ratio of PEG-to-enzyme from 1.1 to 7.1 resulted in a more than twofold decrease in enzyme activity. Controlling the water activity did not prevent the drop in activity. To investigate the possible origin of the activity changes, Fourier transform infrared (FTIR) spectroscopy experiments were conducted. It was found that PEGylation reduced lyophilization-induced structural perturbations, but exposure to the organic solvents caused structural perturbations. These perturbations were more pronounced in polar than in apolar solvents. The pronounced activity drop in polar solvents at increasing PEG-modification levels correlated with an increasing level of solvent-induced structural perturbations. This correlation was less pronounced in apolar solvents where both, activity drop and structural perturbations, were less pronounced at increasing PEGylation levels. In summary, PEG-modified alpha-chymotrypsin might be an interesting system to catalyze reactions, particularly in apolar organic solvents.
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Affiliation(s)
- Betzaida Castillo
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, P.O. Box 23346, San Juan, Puerto Rico
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20
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Affiliation(s)
- Valerie Daggett
- Department of Medicinal Chemistry, Box 357610, University of Washington, Seattle, Washington 98195-7610, USA
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21
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Eppler RK, Komor RS, Huynh J, Dordick JS, Reimer JA, Clark DS. Water dynamics and salt-activation of enzymes in organic media: mechanistic implications revealed by NMR spectroscopy. Proc Natl Acad Sci U S A 2006; 103:5706-10. [PMID: 16585507 PMCID: PMC1458637 DOI: 10.1073/pnas.0601113103] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Indexed: 11/18/2022] Open
Abstract
Deuterium spin relaxation was used to examine the motion of enzyme-bound water on subtilisin Carlsberg co-lyophilized with inorganic salts for activation in different organic solvents. Spectral editing was used to ensure that the relaxation times were associated with relatively mobile deuterons, which were contributed almost entirely by D(2)O rather than hydrogen-deuteron exchange on the protein. The results indicate that the timescale of motion for residual water molecules on the biocatalyst, (tau(c))(D(2)O), in hexane decreased from 65 ns (salt-free) to 0.58 ns (98% CsF) as (k(cat)/K(M))(app) of the biocatalyst preparation increased from 0.092 s(-1) x M(-1) (salt-free) to 1,140 s(-1) x M(-1) (98% CsF). A similar effect was apparent in acetone; the timescale decreased from 24 ns (salt-free) to 2.87 ns (98% KF), with a corresponding increase in (k(cat)/K(M))(app) of 0.140 s(-1) x M(-1) (salt-free) to 12.8 s(-1) x M(-1) (98% KF). Although a global correlation between water mobility and enzyme activity was not evident, linear correlations between ln[(k(cat)/K(M))(app)] and (tau(c))(D(2)O) were obtained for salt-activated enzyme preparations in both hexane and acetone. Furthermore, a direct correlation was evident between (k(cat)/K(M))(app) and the total amount of mobile water per mass of enzyme. These results suggest that increases in enzyme-bound water mobility mediated by the presence of salt act as a molecular lubricant and enhance enzyme flexibility in a manner functionally similar to temperature. Greater flexibility may permit a larger degree of local transition-state mobility, reflected by a more positive entropy of activation, for the salt-activated enzyme compared with the salt-free enzyme. This increased mobility may contribute to the dramatic increases in biocatalyst activity.
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Affiliation(s)
- Ross K. Eppler
- Department of Chemical Engineering, University of California, Berkeley, CA 94720; and
| | - Russell S. Komor
- Department of Chemical Engineering, University of California, Berkeley, CA 94720; and
| | - Joyce Huynh
- Department of Chemical Engineering, University of California, Berkeley, CA 94720; and
| | - Jonathan S. Dordick
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Jeffrey A. Reimer
- Department of Chemical Engineering, University of California, Berkeley, CA 94720; and
| | - Douglas S. Clark
- Department of Chemical Engineering, University of California, Berkeley, CA 94720; and
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22
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Hirakawa H, Kamiya N, Kawarabayashi Y, Nagamune T. Log P effect of organic solvents on a thermophilic alcohol dehydrogenase. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2005; 1748:94-9. [PMID: 15752697 DOI: 10.1016/j.bbapap.2004.12.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2004] [Revised: 12/16/2004] [Accepted: 12/17/2004] [Indexed: 11/30/2022]
Abstract
An alcohol dehydrogenase from the hyperthermophilic archaeon Aeropyrum pernix was activated by water-miscible organic solvents. This activation was influenced by the kind and the concentration of the added organic solvents. The k(cat) was increased by a factor of over ten when the mole fraction of acetonitrile was 0.1. This effect was large when organic solvents with large log P values were added. In fact, the k(cat) showed a strong positive correlation with the log P value of the mixed solvent at a constant mole fraction of water, while it was not affected by the kind of organic solvents added. Both the activation enthalpy and the entropy decreased with an increase in log P. The contribution of the activation enthalpy to the free energy of activation was larger than that of the activation entropy, and the free energy of activation decreased with an increase in log P.
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Affiliation(s)
- Hidehiko Hirakawa
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
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23
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Halling PJ. What can we learn by studying enzymes in non-aqueous media? Philos Trans R Soc Lond B Biol Sci 2004; 359:1287-96; discussion 1296-7, 1323-8. [PMID: 15306383 PMCID: PMC1693404 DOI: 10.1098/rstb.2004.1505] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
What is the role of water in enzyme structure and function? One approach to answers should come from studies in which the amount of water present is a variable. In the absence of bulk liquid water, effective monitoring of enzyme action requires an alternative fluid medium through which substrates and products may be transported. The past 20 years have seen quite extensive study of enzyme behaviour when reactants are transferred via a bulk phase that is an organic liquid, a supercritical fluid or a gas. Some lipases, at least, remain highly active with only a few, if any, residual water molecules. Many enzymes seem to require larger amounts of water, but still not a liquid water phase. There are hysteresis effects on both the amount of bound water and the observed catalytic activity. Increasing hydration promotes mobility of the enzyme molecule, as revealed by various techniques, and there are correlations with catalytic activity. There are other plausible roles for hydration, such as opening up proton conduction pathways.
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Affiliation(s)
- Peter J Halling
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, UK.
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24
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Altreuter DH, Dordick JS, Clark DS. Solid-phase peptide synthesis by ion-paired alpha-chymotrypsin in nonaqueous media. Biotechnol Bioeng 2003; 81:809-17. [PMID: 12557314 DOI: 10.1002/bit.10536] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Solid-phase synthesis of dipeptides in low-water media was achieved using AOT ion-paired alpha-chymotrypsin solubilized in organic solvents. Multiple solvents and systematic variation of water activity, a(w), were used to examine the rate of coupling between N-alpha-benzyloxycarbonyl-L-phenylalanine methyl ester (Z-Phe-OMe) and leucine as a function of the reaction medium for both solid-phase and solution-phase reactions. In solution, the observed maximum reaction rate in a given solvent generally correlated with measures of hydrophobicity such as the log of the 1-octanol/water partitioning coefficient (log P) and the Hildebrand solubility parameter. The maximum rate for solution-phase synthesis (13 mmol/h g-enzyme) was obtained in a 90/10 (v/v) isooctane/tetrahydrofuran solvent mixture at an a(w) of 0.30. For the synthesis of dipeptides from solid-phase leucine residues, the highest synthetic rates (0.14-1.3 mmol/h g-enzyme) were confined to solvent environments that fell inside abruptly defined regions of solvent parameter space (e.g., log P > 2.3 and normalized electron acceptance index <0.13). The maximum rate for solid-phase synthesis was obtained in a 90/10 (v/v) isooctane/tetrahydrofuran solvent mixture at an a(w) of 0.14. In 90/10 and 70/30 (v/v) isooctane/tetrahydrofuran environments with a(w) set to 0.14, seven different N-protected dipeptides were synthesized on commercially available Tentagel support with yields of 74-98% in 24 h.
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Affiliation(s)
- David H Altreuter
- Department of Chemical Engineering, University of California, Berkeley, California 94720-1462, USA
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25
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Ueji SI, Taniguchi T, Okamoto T, Watanabe K, Ebara Y, Ohta H. Flexibility of Lipase Brought About by Solvent Effects Controls Its Enantioselectivity in Organic Media. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2003. [DOI: 10.1246/bcsj.76.399] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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26
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Ono S, Taguma T, Kuroki S, Ando I, Kimura H, Yamauchi K. A study of hydrogen-bonding of amino acids, peptides and polypeptides in the solid state as a function of temperature by static 2H NMR method. J Mol Struct 2002. [DOI: 10.1016/s0022-2860(01)00770-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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27
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Hansson T, Andersson M, Wehtje E, Adlercreutz P. Influence of water activity on the competition between β-glycosidase-catalysed transglycosylation and hydrolysis in aqueous hexanol. Enzyme Microb Technol 2001. [DOI: 10.1016/s0141-0229(01)00421-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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28
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Rees DG, Halling PJ. Chemical modification probes accessibility to organic phase: proteins on surfaces are more exposed than in lyophilized powders. Enzyme Microb Technol 2001; 28:282-292. [PMID: 11166823 DOI: 10.1016/s0141-0229(00)00358-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Chemical modification of myoglobin and cutinase suspended in n-hexane by acyl chlorides and iodine was monitored by electrospray mass spectrometry. The general rate of modification was always much faster for protein adsorbed to supports (silica or polypropylene) than for lyophilized powders. Modification rates were slower for larger acyl chlorides, particularly with lyophilized powders. About 20% of the protein molecules in lyophilized powders were modified much more quickly than the rest, a fraction consistent with those exposed on the surface of the solid. It appears that access to most of the molecules in lyophilized powders requires a very slow stage of solid-phase diffusion. This has been neglected in previous discussion of mass transfer limitation of lyophilized enzymes in organic media, and would not be revealed by the experimental evidence used to dismiss it. Studies of the effects of particle size and dilution with inactive protein are only sensitive to diffusion in liquid-filled pores, not through the solid phase. Slow solid-phase diffusion is not required for access to most support-adsorbed proteins, which is probably a major contributory factor to their enhanced catalytic efficiency in organic media. Hydration of lyophilized proteins accelerates chemical modification rates, as it does their catalytic activity. The main site of reaction of acyl chlorides in organic media is not amino groups (which are probably ion-paired), but is likely to be hydroxyl groups instead.
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Affiliation(s)
- D G. Rees
- Departments of Bioscience and Biotechnology and Pure and Applied Chemistry, University of Strathclyde, G1 1XW, Glasgow, UK
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29
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Abstract
The technological utility of enzymes can be enhanced greatly by using them in organic solvents rather than their natural aqueous reaction media. Studies over the past 15 years have revealed not only that this change in solvent is feasible, but also that in such seemingly hostile environments enzymes can catalyse reactions impossible in water, become more stable, and exhibit new behaviour such as 'molecular memory'. Of particular importance has been the discovery that enzymatic selectivity, including substrate, stereo-, regio- and chemoselectivity, can be markedly affected, and sometimes even inverted, by the solvent. Enzyme-catalysed reactions in organic solvents, and even in supercritical fluids and the gas phase, have found numerous potential applications, some of which are already commercialized.
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Affiliation(s)
- A M Klibanov
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139, USA.
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30
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Chemical modification probes accessibility to organic phase: proteins on surfaces are more exposed than in lyophilized powders. Enzyme Microb Technol 2000; 27:549-559. [PMID: 11024517 DOI: 10.1016/s0141-0229(00)00240-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Chemical modification of myoglobin and cutinase suspended in n-hexane by acyl chlorides and iodine was monitored by electrospray mass spectrometry. The general rate of modification was always much faster for protein adsorbed to supports (silica or polypropylene) than for lyophilized powders. Modification rates were slower for larger acyl chlorides, particularly with lyophilized powders. About 20% of the protein molecules in lyophilized powders were modified much more quickly than the rest, a fraction consistent with those exposed on the surface of the solid. It appears that access to most of the molecules in lyophilized powders requires a very slow stage of solid-phase diffusion. This has been neglected in previous discussion of mass transfer limitation of lyophilized enzymes in organic media, and would not be revealed by the experimental evidence used to dismiss it. Studies of the effects of particle size and dilution with inactive protein are only sensitive to diffusion in liquid-filled pores, not through the solid phase. Slow solid-phase diffusion is not required for access to most support-adsorbed proteins, which is probably a major contributory factor to their enhanced catalytic efficiency in organic media. Hydration of lyophilized proteins accelerates chemical modification rates, as it does their catalytic activity. The main site of reaction of acyl chlorides in organic media is not amino groups (which are probably ion-paired), but is likely to be hydroxyl groups instead.
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31
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33
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de Carvalho IB, de Sampaio TC, Barreiros S. Solvent effects on the catalytic activity of subtilisin suspended in compressed gases. Biotechnol Bioeng 2000; 49:399-404. [DOI: 10.1002/(sici)1097-0290(19960220)49:4<399::aid-bit6>3.0.co;2-k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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34
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Abstract
The key role played by counter-ions with enzymes in low-water systems has become better appreciated with, for example, large effects on enantioselectivity. In low-dielectric media, counter-ions will associate strongly with charges in the protein or its substrates. Studies of temperature dependence have shown that hard-to-model entropies have a significant effect on behaviour, including enantioselectivity. Evidence has been presented that the supramolecular organisation of enzyme molecules can have important effects on behaviour, for example collapse of microstructure in cross-linked crystals.
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Affiliation(s)
- P J Halling
- Department of Chemistry, University of Strathclyde, Glasgow, G1 1XW, UK.
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35
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Kameda T, Ohkawa Y, Yoshizawa K, Nakano E, Hiraoki T, Ulrich AS, Asakura T. Dynamics of the Tyrosine Side Chain in Bombyx mori and Samia cynthia ricini Silk Fibroin Studied by Solid State 2H NMR. Macromolecules 1999. [DOI: 10.1021/ma991344g] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tsunenori Kameda
- Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-5588, Japan, Department of Applied Physics, Hokkaido University, Sapporo 060-8628, Japan, and Institut für Molekularbiologie, Friedrich-Schiller-Universität Jena, Winzerlaer Strasse 10, 07745 Jena, Germany
| | - Youhei Ohkawa
- Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-5588, Japan, Department of Applied Physics, Hokkaido University, Sapporo 060-8628, Japan, and Institut für Molekularbiologie, Friedrich-Schiller-Universität Jena, Winzerlaer Strasse 10, 07745 Jena, Germany
| | - Keiko Yoshizawa
- Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-5588, Japan, Department of Applied Physics, Hokkaido University, Sapporo 060-8628, Japan, and Institut für Molekularbiologie, Friedrich-Schiller-Universität Jena, Winzerlaer Strasse 10, 07745 Jena, Germany
| | - Emi Nakano
- Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-5588, Japan, Department of Applied Physics, Hokkaido University, Sapporo 060-8628, Japan, and Institut für Molekularbiologie, Friedrich-Schiller-Universität Jena, Winzerlaer Strasse 10, 07745 Jena, Germany
| | - Toshifumi Hiraoki
- Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-5588, Japan, Department of Applied Physics, Hokkaido University, Sapporo 060-8628, Japan, and Institut für Molekularbiologie, Friedrich-Schiller-Universität Jena, Winzerlaer Strasse 10, 07745 Jena, Germany
| | - Anne S. Ulrich
- Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-5588, Japan, Department of Applied Physics, Hokkaido University, Sapporo 060-8628, Japan, and Institut für Molekularbiologie, Friedrich-Schiller-Universität Jena, Winzerlaer Strasse 10, 07745 Jena, Germany
| | - Tetsuo Asakura
- Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-5588, Japan, Department of Applied Physics, Hokkaido University, Sapporo 060-8628, Japan, and Institut für Molekularbiologie, Friedrich-Schiller-Universität Jena, Winzerlaer Strasse 10, 07745 Jena, Germany
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36
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Carrasquillo KG, Costantino HR, Cordero RA, Hsu CC, Griebenow K. On the structural preservation of recombinant human growth hormone in a dried film of a synthetic biodegradable polymer. J Pharm Sci 1999; 88:166-73. [PMID: 9950633 DOI: 10.1021/js980272o] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this work we describe the structural investigation of the model protein recombinant human growth hormone (rhGH) under conditions relevant to polymeric sustained-delivery depots, including the dried protein entrapped in a film of poly(DL-lactic-co-glycolic)acid. At each step of the procedure, dehydration of rhGH by lyophilization, suspension in methylene chloride, and drying from that suspension, the structure of rhGH was probed noninvasively using Fourier transform infrared (FTIR) spectroscopy. We found that the structure of rhGH was significantly changed by the dehydration process as indicated by a marked drop in the alpha-helix content and increase in the beta-sheet content. Subsequent suspension of this powder in methylene chloride, drying from that suspension, and drying from a methylene chloride/PLGA solution introduced only minor additional structural changes when using appropriate conditions. This result is likely due to the limited molecular mobility of proteins in nonprotein-dissolving organic solvents. Finally, when rhGH was co-lyophilized with the lyoprotectant trehalose, which preserves the secondary structure, the rhGH entrapped in the PLGA matrix also had a nativelike secondary structure.
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Affiliation(s)
- K G Carrasquillo
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, P.O. Box 23346, San Juan 00931-3346, USA
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37
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Partridge J, Dennison PR, Moore BD, Halling PJ. Activity and mobility of subtilisin in low water organic media: hydration is more important than solvent dielectric. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1386:79-89. [PMID: 9675249 DOI: 10.1016/s0167-4838(98)00086-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The relationship between hydration, catalytic activity and protein dynamics was investigated for subtilisin Carlsberg in organic solvents with low water content. The organic media were cyclohexane, dichloromethane or acetonitrile, with controlled thermodynamic water activity (aw). Catalytic rate profiles showed the same dependence on aw for the three different solvents. The structural mobility of the enzyme in air and organic media was probed by proton solid-state NMR relaxation measurements. Both spin-lattice relaxation time (T1 ) and line width at half height (apparent spin-spin relaxation time (T2)) were determined for protein which was exchanged and hydrated with D2O. We found NMR relaxation was much more dependent on aw than medium identity (despite very different dielectrics) showing that enzyme hydration is the primary determinant of mobility. Results suggest that initial hydration up to aw 0.22 causes rigidification of part of the protein structure. As aw is increased further, enzyme mobility is found to increase. Above aw 0.44, a large increase in the proportion of more mobile protons coincides with a steep rise in catalytic activity for the enzyme in each of the solvents studied.
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Affiliation(s)
- J Partridge
- Department of Pure and Applied Chemistry, Royal College Building, University of Strathclyde, 204 George Street, Glasgow G1 1XW, UK.
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38
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Almeida M, Ruivo R, Maia C, Freire L, Corrêa de Sampaio T, Barreiros S. Novozym 435 Activity in Compressed Gases. Water Activity and Temperature Effects. Enzyme Microb Technol 1998. [DOI: 10.1016/s0141-0229(97)00241-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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39
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Abstract
Water is fundamental for enzyme action and for formation of the three-dimensional structure of proteins. Hence, it may be assumed that studies on the interplay between water and enzymes can yield insight into enzyme function and formation. This has proven correct, because the numerous studies that have been made on the behavior of water-soluble and membrane enzymes in systems with a low water content (reverse micelles or enzymes suspended in nonpolar organic solvents) have revealed properties of enzymes that are not easily appreciated in aqueous solutions. In the low water systems, it has been possible to probe the relation between solvent and enzyme kinetics, as well as some of the factors that affect enzyme thermostability and catalysis. Furthermore, the studies show that low water environments can be used to stabilize conformers that exhibit unsuspected catalytic properties, as well as intermediates of enzyme function and formation that in aqueous media have relatively short life-times. The structure of enzymes in these unnatural conditions is actively being explored.
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40
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41
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Hiraoki T, Kogame A, Nishi N, Tsutsumi A. Deuterium NMR studies on phenyl ring dynamics of poly(l-phenylalanine). J Mol Struct 1998. [DOI: 10.1016/s0022-2860(97)00257-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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42
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Toba S, Merz KM. The Concept of Solvent Compatibility and Its Impact on Protein Stability and Activity Enhancement in Nonaqueous Solvents. J Am Chem Soc 1997. [DOI: 10.1021/ja970629a] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Samuel Toba
- Contribution from the Department of Chemistry, The Pennsylvania State University, 152 Davey Laboratory, University Park, Pennsylvania 16802
| | - Kenneth M. Merz
- Contribution from the Department of Chemistry, The Pennsylvania State University, 152 Davey Laboratory, University Park, Pennsylvania 16802
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43
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Long JR, Ebelhäuser R, Griffin RG. 2H NMR Line Shapes and Spin−Lattice Relaxation in Ba(ClO3)2·2H2O. J Phys Chem A 1997. [DOI: 10.1021/jp962116g] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Joanna R. Long
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Rainer Ebelhäuser
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - R. G. Griffin
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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44
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Protein Dynamics: A Theoretical Perspective. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s1569-2558(08)60481-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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45
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Mingarro I, González-Navarro H, Braco L. Trapping of different lipase conformers in water-restricted environments. Biochemistry 1996; 35:9935-44. [PMID: 8703968 DOI: 10.1021/bi960191b] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Based on a recently reported strategy to rationally activate lipolytic enzymes for use in nonaqueous media [Mingarro, I., et al. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 3308-3312], we compared the behavior in water-restricted environments of activated vs nonactivated forms of different lipases toward their natural substrates, triacylglycerols. To this end, nine lipases from varied origins (mammalian, fungal, and bacterial) were assayed using simple acidolyses as nonaqueous model reactions. The experimental results for several (though not all) lipases, discussed in the light of current structural and functional information, were collectively consistent with a model where, depending on the "history" of sample preparation, basically two different conformers (open and closed) of the lipase can be trapped (and assayed) in the nonaqueous medium. In particular, for a few prototypic lipases investigated in more detail, the following were shown: (i) the activation strategy permitted them to rationally overcome their reported reluctance to convert saturated, long-chain triglycerides, providing quantifiable nonaqueous rate accelerations of up to 3 orders of magnitude; (ii) the activated conformer exhibited a markedly higher ability than its nonactivated counterpart to bind a ligand (nonhydrolyzable phospholipid) in the nonaqueous medium; and (iii) a clearly distinct selectivity profile toward the substrate chain length was obtained for either conformer.
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Affiliation(s)
- I Mingarro
- Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Valencia, Burjassot, Spain
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46
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de Sampaio TC, Melo RB, Moura TF, Michel S, Barreiros S. Solvent effects on the catalytic activity of subtilisin suspended in organic solvents. Biotechnol Bioeng 1996; 50:257-64. [DOI: 10.1002/(sici)1097-0290(19960505)50:3<257::aid-bit4>3.0.co;2-f] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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47
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48
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Pourplanche C, Lambert C, Berjot M, Marx J, Chopard C, Alix A, Larreta-Garde V. Conformational changes of lipoxygenase (LOX) in modified environments. Contribution to the variation in specificity of soybean LOX type 1. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)31734-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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49
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Abstract
The discovery that enzymes possess catalytic activity in organic solvents has made it possible to address the question of the influence of the reaction medium on enzymatic specificity. Recently, the substrate specificity, enantioselectivity, prochiral selectivity, regioselectivity, and chemoselectivity of enzymes have been found to dramatically depend on the nature of the solvent. This review discusses the scope, possible mechanisms, and implications of this phenomenon, as well as directions of future research in the area.
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Affiliation(s)
- C R Wescott
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139
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