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Title: A Rac1--GDP trimer complex binds zinc with tetrahedral and octahedral coordination, displacing magnesium

Abstract

The Rho family of small GTPases represent well characterized signaling molecules that regulate many cellular functions such as actin cytoskeletal arrangement and the cell cycle by acting as molecular switches. A Rac1-GDP-Zn complex has been crystallized in space group P3221 and its crystal structure has been solved at 1.9 {angstrom} resolution. These trigonal crystals reveal the unexpected ability of Rac1 to coordinate Zn atoms in a tetrahedral fashion by use of its biologically relevant switch I and switch II regions. Upon coordination of zinc, the switch I region is stabilized in the GDP-bound conformation and contributes to a Rac1 trimer in the asymmetric unit. Zinc coordination causes switch II to adopt a novel conformation with a symmetry-related molecule. Additionally, zinc was found to displace magnesium from its octahedral coordination at switch I, although GDP binding remained stable. This structure represents the first reported Rac1-GDP-Zn complex, which further underscores the conformational flexibility and versatility of the small GTPase switch regions.

Authors:
;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
979987
Report Number(s):
BNL-92905-2010-JA
TRN: US201015%%1372
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Acta Crystallographica Section D: Biological Crystallography; Journal Volume: 63
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 59 BASIC BIOLOGICAL SCIENCES; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; ACTIN; ATOMS; CELL CYCLE; COORDINATES; CRYSTAL STRUCTURE; CRYSTALS; FLEXIBILITY; FUNCTIONS; MAGNESIUM; MOLECULES; RESOLUTION; SPACE GROUPS; SWITCHES; USA; USES; WELLS; ZINC; national synchrotron light source

Citation Formats

Prehna, G., and Stebbins, C. A Rac1--GDP trimer complex binds zinc with tetrahedral and octahedral coordination, displacing magnesium. United States: N. p., 2007. Web. doi:10.1107/S0907444907010888.
Prehna, G., & Stebbins, C. A Rac1--GDP trimer complex binds zinc with tetrahedral and octahedral coordination, displacing magnesium. United States. doi:10.1107/S0907444907010888.
Prehna, G., and Stebbins, C. Mon . "A Rac1--GDP trimer complex binds zinc with tetrahedral and octahedral coordination, displacing magnesium". United States. doi:10.1107/S0907444907010888.
@article{osti_979987,
title = {A Rac1--GDP trimer complex binds zinc with tetrahedral and octahedral coordination, displacing magnesium},
author = {Prehna, G. and Stebbins, C},
abstractNote = {The Rho family of small GTPases represent well characterized signaling molecules that regulate many cellular functions such as actin cytoskeletal arrangement and the cell cycle by acting as molecular switches. A Rac1-GDP-Zn complex has been crystallized in space group P3221 and its crystal structure has been solved at 1.9 {angstrom} resolution. These trigonal crystals reveal the unexpected ability of Rac1 to coordinate Zn atoms in a tetrahedral fashion by use of its biologically relevant switch I and switch II regions. Upon coordination of zinc, the switch I region is stabilized in the GDP-bound conformation and contributes to a Rac1 trimer in the asymmetric unit. Zinc coordination causes switch II to adopt a novel conformation with a symmetry-related molecule. Additionally, zinc was found to displace magnesium from its octahedral coordination at switch I, although GDP binding remained stable. This structure represents the first reported Rac1-GDP-Zn complex, which further underscores the conformational flexibility and versatility of the small GTPase switch regions.},
doi = {10.1107/S0907444907010888},
journal = {Acta Crystallographica Section D: Biological Crystallography},
number = ,
volume = 63,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}