An Allosteric Pathway Revealed in the Ribosome Binding Stress Factor BipA

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Biophysical Journal

DOI:https://doi.org/10.1016/j.bpj.2008.12.3035· OSTI ID:1019654

Makanji, H; deLivron, M; Robinson, V

BipA is a highly conserved prokaryotic GTPase that functions as a master regulator of stress and virulence processes in bacteria. It is a member of the translational factor family of GTPases along with EF-G, IF-2 and LepA. Structural and biochemical data suggest that ribosome binding specificity for each member of this family lies in an effector domain. As with other bacterial GTPases, the ribosome binding and GTPase activities of this protein are tightly coupled. However, the mechanism by which this occurs is still unknown. A series of experiments have been designed to probe structural features of the protein to see if we can pinpoint specific areas of BipA, perhaps even individual residues, which are important to its association with the ribosome. Included in the list are the C-terminal effector domain of the protein, which is distinct to the BipA family of proteins, and amino acid residues in the switch I and II regions of the G domain. Using sucrose density gradients, we have shown that the C-terminal domain is required in order for BipA to bind to the ribosome. Moreover, deletion of this domain increases the GTP hydrolysis rates of the protein, likely through relief of inhibitory contacts. Additional evidence has revealed an allosteric connection between the conformationally flexible switch II region and the C-terminal domain of BipA. Site directed mutagenesis, sucrose gradients and malachite green assays are being used to elucidate the details of this coupling.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: DOE - OFFICE OF SCIENCE
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1019654
• Report Number(s): BNL--95500-2011-JA
• Journal Information: Biophysical Journal, Journal Name: Biophysical Journal Journal Issue: 3 Vol. 96; ISSN 0006-3495; ISSN BIOJAU
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
99 GENERAL AND MISCELLANEOUS
AMINO ACIDS
BACTERIA
HYDROLYSIS
MUTAGENESIS
PROBES
PROTEINS
RESIDUES
RIBOSOMES
SACCHAROSE
SPECIFICITY
VIRULENCE
national synchrotron light source