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Structure and proposed mechanism of l ‐α‐glycerophosphate oxidase from Mycoplasma pneumoniae
Author(s) -
Elkhal Callia K.,
Kean Kelsey M.,
Parsonage Derek,
Maenpuen Somchart,
Chaiyen Pimchai,
Claiborne Al,
Karplus P. Andrew
Publication year - 2015
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.13233
Subject(s) - mycoplasma pneumoniae , streptococcus pneumoniae , recombinant dna , biochemistry , oxidase test , biology , chemistry , residue (chemistry) , stereochemistry , microbiology and biotechnology , enzyme , gene , archaeology , history , pneumonia , antibiotics
The formation of H 2 O 2 by the FAD ‐dependent l ‐α‐glycerophosphate oxidase (GlpO) is important for the pathogenesis of Streptococcus pneumoniae and Mycoplasma pneumoniae . The structurally known GlpO from Streptococcus sp. ( Ssp GlpO) is similar to the pneumococcal protein ( Sp GlpO) and provides a guide for drug design against that target. However, M. pneumoniae GlpO ( Mp GlpO), having < 20% sequence identity with structurally known GlpOs, appears to represent a second type of GlpO that we designate as type II GlpOs. In the present study, the recombinant His‐tagged Mp GlpO structure is described at an approximate resolution of 2.5 Å, solved by molecular replacement using, as a search model, the Bordetella pertussis protein 3253 ( Bp 3253), comprising a protein of unknown function solved by structural genomics efforts. Recombinant Mp GlpO is an active oxidase with a turnover number of approximately 580 min −1 , whereas Bp 3253 showed no GlpO activity. No substantial differences exist between the oxidized and dithionite‐reduced Mp GlpO structures. Although, no liganded structures were determined, a comparison with the tartrate‐bound Bp 3253 structure and consideration of residue conservation patterns guided the construction of a model for l ‐α‐glycerophosphate (Glp) recognition and turnover by Mp GlpO. The predicted binding mode also appears relevant for the type I GlpOs (such as Ssp GlpO) despite differences in substrate recognition residues, and it implicates a histidine conserved in type I and II Glp oxidases and dehydrogenases as the catalytic acid/base. The present study provides a solid foundation for guiding further studies of the mitochondrial Glp dehydrogenases, as well as for continued studies of M. pneumoniae and S. pneumoniae glycerol metabolism and the development of novel therapeutics targeting Mp GlpO and Sp GlpO. Database Structural data have been deposited in the Protein Data Bank under accession numbers 4X9M (oxidized) and 4X9N (reduced).