Dataset Information

Binding structures of tri-N-acetyl-?-glucosamine in hen egg white lysozyme using molecular dynamics with a polarizable force field.

ABSTRACT: Lysozyme is a well-studied enzyme that hydrolyzes the ?-(1,4)-glycosidic linkage of N-acetyl-?-glucosamine (NAG)(n) oligomers. The active site of hen egg-white lysozyme (HEWL) is believed to consist of six subsites, A-F that can accommodate six sugar residues. We present studies exploring the use of polarizable force fields in conjunction with all-atom molecular dynamics (MD) simulations to analyze binding structures of complexes of lysozyme and NAG trisaccharide, (NAG)(3). MD trajectories are applied to analyze structures and conformation of the complex as well as protein-ligand interactions, including the hydrogen-bonding network in the binding pocket. Two binding modes (ABC and BCD) of (NAG)(3) are investigated independently based on a fixed-charge model and a polarizable model. We also apply molecular mechanics with generalized born and surface area (MM-GBSA) methods based on MD using both nonpolarizable and polarizable force fields to compute binding free energies. We also study the correlation between root-mean-squared deviation and binding free energies of the wildtype and W62Y mutant; we find that for this prototypical system, approaches using the MD trajectories coupled with implicit solvent models are equivalent for polarizable and fixed-charge models.

SUBMITTER: Zhong Y

PROVIDER: S-EPMC4214157 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature

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Publications

Binding structures of tri-N-acetyl-β-glucosamine in hen egg white lysozyme using molecular dynamics with a polarizable force field.

Zhong Yang Y Patel Sandeep S

Journal of computational chemistry 20121029 3

Lysozyme is a well-studied enzyme that hydrolyzes the β-(1,4)-glycosidic linkage of N-acetyl-β-glucosamine (NAG)(n) oligomers. The active site of hen egg-white lysozyme (HEWL) is believed to consist of six subsites, A-F that can accommodate six sugar residues. We present studies exploring the use of polarizable force fields in conjunction with all-atom molecular dynamics (MD) simulations to analyze binding structures of complexes of lysozyme and NAG trisaccharide, (NAG)(3). MD trajectories are a ...[more]

PMID: 23109228

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Project description:Chemical bonding at the active site of hen egg-white lysozyme (HEWL) is analyzed on the basis of Bader's quantum theory of atoms in molecules [QTAIM; Bader (1994), Atoms in Molecules: A Quantum Theory. Oxford University Press] applied to electron-density maps derived from a multipole model. The observation is made that the atomic displacement parameters (ADPs) of HEWL at a temperature of 100?K are larger than ADPs in crystals of small biological molecules at 298?K. This feature shows that the ADPs in the cold crystals of HEWL reflect frozen-in disorder rather than thermal vibrations of the atoms. Directly generalizing the results of multipole studies on small-molecule crystals, the important consequence for electron-density analysis of protein crystals is that multipole parameters cannot be independently varied in a meaningful way in structure refinements. Instead, a multipole model for HEWL has been developed by refinement of atomic coordinates and ADPs against the X-ray diffraction data of Wang and coworkers [Wang et al. (2007), Acta Cryst. D63, 1254-1268], while multipole parameters were fixed to the values for transferable multipole parameters from the ELMAM2 database [Domagala et al. (2012), Acta Cryst. A68, 337-351] . Static and dynamic electron densities based on this multipole model are presented. Analysis of their topological properties according to the QTAIM shows that the covalent bonds possess similar properties to the covalent bonds of small molecules. Hydrogen bonds of intermediate strength are identified for the Glu35 and Asp52 residues, which are considered to be essential parts of the active site of HEWL. Furthermore, a series of weak C-H...O hydrogen bonds are identified by means of the existence of bond critical points (BCPs) in the multipole electron density. It is proposed that these weak interactions might be important for defining the tertiary structure and activity of HEWL. The deprotonated state of Glu35 prevents a distinction between the Phillips and Koshland mechanisms.

Dataset Information

Binding structures of tri-N-acetyl-?-glucosamine in hen egg white lysozyme using molecular dynamics with a polarizable force field.

Publications

Binding structures of tri-N-acetyl-β-glucosamine in hen egg white lysozyme using molecular dynamics with a polarizable force field.

Similar Datasets

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