Cloning, expression, purification, crystallization and preliminary X-ray analysis of the 31 kDa<i>Vibrio cholerae</i>heat-shock protein VcHsp31

Das, Samir; Dey, Sanjay; Roy, Trina; Sen, U.

doi:10.1107/s1744309111032970

Cited by 1 publication

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“…Cloning, expression, purification and crystallization of Vc Hsp31 have been published earlier [ 14 ]. In brief, Vc Hsp31 was cloned in pET28a + vector, overexpressed in E .…”

Section: Methodsmentioning

confidence: 99%

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Structural and biochemical studies on Vibrio cholerae Hsp31 reveals a novel dimeric form and Glutathione-independent Glyoxalase activity

et al. 2017

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Vibrio cholerae experiences a highly hostile environment at human intestine which triggers the induction of various heat shock genes. The hchA gene product of V. cholerae O395, referred to a hypothetical intracellular protease/amidase VcHsp31, is one such stress-inducible homodimeric protein. Our current study demonstrates that VcHsp31 is endowed with molecular chaperone, amidopeptidase and robust methylglyoxalase activities. Through site directed mutagenesis coupled with biochemical assays on VcHsp31, we have confirmed the role of residues in the vicinity of the active site towards amidopeptidase and methylglyoxalase activities. VcHsp31 suppresses the aggregation of insulin in vitro in a dose dependent manner. Through crystal structures of VcHsp31 and its mutants, grown at various temperatures, we demonstrate that VcHsp31 acquires two (Type-I and Type-II) dimeric forms. Type-I dimer is similar to EcHsp31 where two VcHsp31 monomers associate in eclipsed manner through several intersubunit hydrogen bonds involving their P-domains. Type-II dimer is a novel dimeric organization, where some of the intersubunit hydrogen bonds are abrogated and each monomer swings out in the opposite directions centering at their P-domains, like twisting of wet cloth. Normal mode analysis (NMA) of Type-I dimer shows similar movement of the individual monomers. Upon swinging, a dimeric surface of ~400Å2, mostly hydrophobic in nature, is uncovered which might bind partially unfolded protein substrates. We propose that, in solution, VcHsp31 remains as an equilibrium mixture of both the dimers. With increase in temperature, transformation to Type-II form having more exposed hydrophobic surface, occurs progressively accounting for the temperature dependent increase of chaperone activity of VcHsp31.

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“…Cloning, expression, purification and crystallization of Vc Hsp31 have been published earlier [ 14 ]. In brief, Vc Hsp31 was cloned in pET28a + vector, overexpressed in E .…”

Section: Methodsmentioning

confidence: 99%

“…The hchA gene product of V . cholerae O395, Vc Hsp31, which belongs to DJ-1/PfpI superfamily, is referred as a hypothetical intracellular protease/amidase [ 14 ]. However, neither any functional study nor the molecular basis of these functions is reported so far for Vc Hsp31.…”

Section: Introductionmentioning

confidence: 99%