Isolation of Two Strong Poly (U) Binding Proteins from Moderate Halophile Halomonas eurihalina and Their Identification as Cold Shock Proteins

Usha Kumari Garapati,Tangirala Suryanarayana,John R Battista

doi:10.1371/journal.pone.0034409

Usha Kumari Garapati, Tangirala Suryanarayana + Show 1 more

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https://doi.org/10.1371/journal.pone.0034409

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Journal: PLoS ONE	Publication Date: Apr 13, 2012
Citations: 12	License type: CC BY 4.0

Affiliation: University of Hyderabad

Abstract

Cold shock proteins (Csp) are known to be expressed in response to sudden decrease in temperature. They are thought to be involved in a number of cellular processes viz., RNA chaperone activity, translation, transcription, nucleoid condensation. During our studies on ribosomal protein S1 in moderate halophile Halomonas eurihalina, we observed the presence of two strong poly (U) binding proteins in abundance in cell extracts from cells grown under normal growth conditions. The proteins can be isolated in a single step using Poly (U) cellulose chromatography. The proteins were identified as major cold shock proteins belonging to Csp A family by MALDI-TOF and bioinformatic analysis. Csp 12 kDa was found in both exponential and stationary phases whereas Csp 8 kDa is found only in exponential phase.

Highlights

Cold shock proteins (CSPs) were known to be induced by a sudden downward shift in temperature [1,2,3,4] and these cold shock proteins are conserved from archaea to eukaryotes
It was reported that the designation of CspA as a major cold shock protein as misnomer because of its abundance in early exponential growth at 37(C in E. coli cells that were never exposed to cold shock
Electrophoretic analysis of proteins strongly bound to Poly (U) cellulose: SDS-PAGE analysis showed that even though elution profile was similar, exponential phase fractions contained two low molecular weight proteins (12 kDa and 8 kDa) where as stationary phase fractions contained one protein (12 kDa) (Fig. 2A & B) and no ribosomal protein S1 was detected

Summary

Introduction

Cold shock proteins (CSPs) were known to be induced by a sudden downward shift in temperature [1,2,3,4] and these cold shock proteins are conserved from archaea to eukaryotes. It was reported that Escherichia coli cold shock proteins are of two types. Class II proteins are present under normal growth conditions but their levels increased by about 10 fold after cold shock treatment. CspA, CspB and CspG were known as major cold shock proteins due to their abundance under cold shock conditions [5]. It was reported that the designation of CspA as a major cold shock protein as misnomer because of its abundance in early exponential growth at 37(C in E. coli cells that were never exposed to cold shock. In spite of extensive research carried out on CspA and other cold shock proteins, their physiological role remains elusive. Structural and functional properties of cold shock proteins from archaea have been reported [10]. Structural, molecular and physiological studies on different cold shock proteins have been reviewed [11,12,13]

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