Title: Molecular Dynamics Simulations of Highly Charged Green Fluorescent Proteins

Abstract

A recent experimental study showed that green fluorescent protein (GFP) that has been mutated to have ultra-high positive or negative net charges, retain their native structure and fluorescent properties while gaining resistance to aggregation under denaturing conditions. These proteins also provide an ideal test case for studying the effects of surface charge on protein structure and dynamics. They have performed classical molecular dynamics (MD) simulations on the near-neutral wildtype GFP and mutants with net charges of -29 and +35. They analyzed the resulting trajectories to quantify differences in structure and dynamics between the three GFPs. This analyses shows that all three proteins are stable over the MD trajectory, with the near-neutral wild type GFP exhibiting somewhat more flexibility than the positive or negative GFP mutants, as measured by the order parameter and changes in phi-psi angles. There are more dramatic differences in the properties of the water and counter ions surrounding the proteins. The water diffusion constant near the protein surface is closer to the value for bulk water in the positively charged GFP than in the other two proteins. Additionally, the positively charged GFP shows a much greater clustering of the counter ions (CL-) near its surface than correspondingmore » counter ions (Na+) near the negatively charged mutant.« less

Authors:

Lau, E Y; Phillips, J L; Colvin, M E

Publication Date:

Thu Mar 26 00:00:00 EDT 2009

Research Org.:

Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

966567

Report Number(s):

LLNL-JRNL-412375
Journal ID: ISSN 0026-8976; MOPHAM; TRN: US200921%%664

DOE Contract Number:  

W-7405-ENG-48

Resource Type:

Journal Article

Journal Name:

Molecular Physics

Additional Journal Information:

Journal Volume: 107; Journal Issue: 8-12; Journal ID: ISSN 0026-8976

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DIFFUSION; FLEXIBILITY; MUTANTS; ORDER PARAMETERS; PROTEIN STRUCTURE; PROTEINS; TRAJECTORIES; WATER