SAXS Data Based Global Shape Analysis of Trigger Factor (TF) Proteins from E. coli, V. cholerae, and P. frigidicola: Resolving the Debate on the Nature of Monomeric and Dimeric Forms.

Rathore, Yogendra S and Dhoke, Reema R and Badmalia, Maulik and Sagar, Amin and Ganguly, Ashish (2015) SAXS Data Based Global Shape Analysis of Trigger Factor (TF) Proteins from E. coli, V. cholerae, and P. frigidicola: Resolving the Debate on the Nature of Monomeric and Dimeric Forms. The journal of physical chemistry. B, 119 (20). pp. 6101-12. ISSN 1520-5207

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Abstract

Dimerization of bacterial chaperone trigger factor (TF) is an inherent protein concentration based property which available biophysical characterization and crystal structures have kept debatable. We acquired small-angle X-ray scattering (SAXS) intensity data from different TF homologues from Escherichia coli (ECTF), Vibrio cholerae (VCTF), and Psychrobacter frigidicola (PFTF) while varying each protein concentration. We found that ECTF and VCTF adopt a compact dimeric shape at higher concentrations which did not resemble the "back-to-back" conformation reported earlier for ECTF from crystallography (PDB ID: 1W26 ). In contrast, PFTF remained monomeric throughout the concentration range 2-90 μM displaying a multimodal open extended conformation. OLIGOMER analysis showed that both the ECTF and VCTF remained completely monomeric at lower concentrations (2-11 μM), while, at higher concentrations (60-90 μM), they adopted a dimeric form. Interestingly, the equilibrium existed in the medium concentration range (>11 and <60 μM), which correlates with the physiological concentration (40-50 μM) of TF in cell cytoplasm. Additionally, circular dichroism data revealed that solution structures of ECTF and VCTF contain predominantly α-helical content, while PFTF contains 310-helical content.

Item Type:	Article
Additional Information:	Copyright of this article belongs to ACS Publications.
Uncontrolled Keywords:	Protein
Subjects:	Q Science > QR Microbiology
Depositing User:	Dr. K.P.S.Sengar
Date Deposited:	13 Jul 2015 12:56
Last Modified:	14 Jul 2015 05:00
URI:	http://crdd.osdd.net/open/id/eprint/1634

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