Crystal structure of a hemerythrin-like protein from Mycobacterium kansasii and homology model of the orthologous Rv2633c protein of M. tuberculosis.

Crystal structure of a hemerythrin-like protein from Mycobacterium kansasii and homology model of the orthologous Rv2633c protein of M. tuberculosis. Biochem J. 2020 Jan 08;: Authors: Ma Z, Abendroth J, Buchko GW, Rohde KH, Davidson VL Abstract Pathogenic and opportunistic mycobacteria have a distinct class of non-heme di-iron hemerythrin-like proteins (HLPs). The first to be isolated was the Rv2633c protein, which plays a role in infection by Mycobacterium tuberculosis (Mtb), but could not be crystallized. This work presents the first crystal structure of an ortholog of Rv2633c, the mycobacterial HLP from Mycobacterium kansasii (Mka). This structure differs from those of hemerythrins and other known HLPs.  It is comprised of five a-helices, whereas all other HLP domains have four. In contrast to other HLPs, the HLP domain is not fused to an additional protein domain. The residues ligating and surrounding the di-iron site are also unique among HLPs. Notably; a tyrosine occupies the position normally held by one of the histidine ligands in hemerythrin. This structure was used to construct a homology model of Rv2633c. The structure of five a-helices is conserved and the di-iron site ligands are identical in Rv2633c. Two residues near the ends of helices in the Mka HLP structure are replaced with prolines in Rv2633c model. This may account for structural perturbations that decrease the solubility of Rv2633c relative to Mka HLP. Cluster...
Source: The Biochemical Journal - Category: Biochemistry Authors: Tags: Biochem J Source Type: research