2y8h
STRUCTURE OF THE FIRST GAF DOMAIN E87G MUTANT OF MYCOBACTERIUM TUBERCULOSIS DOSS
Structural highlights
FunctionDEVS_MYCTU Member of the two-component regulatory system DevR/DevS (DosR/DosS) involved in onset of the dormancy response. May act as a redox sensor (rather than a direct hypoxia sensor); the normal (aerobic growth) state is the Fe(3+) form, while the reduced (anaerobic growth) Fe(2+) form is probably active for phosphate transfer. It is probably reduced by flavin nucleotides such as FMN and FAD. May be the primary sensor for CO. Donates a phosphate group to DevR (DosR).[1] [2] [3] Publication Abstract from PubMedTwo sensor kinases, DosS and DosT, are responsible for recognition of hypoxia in Mycobacterium tuberculosis. Both proteins are structurally similar to each other, but DosS is a redox sensor while DosT binds oxygen. The primary difference between the two proteins is the channel to the heme present in their GAF domains. DosS has a channel that is blocked by E87 while DosT has an open channel. Absorption spectra of DosS mutants with an open channel show that they bind oxygen as DosT does when they are exposed to air, while DosT G85E mutant is oxidized similarly to DosS without formation of an oxy-ferrous form. This suggests that oxygen accessibility to heme is the primary factor governing the oxygen-binding properties of these proteins. Blockage of the channel to heme by the E87 side chain in the GAF domain of Mycobacterium tuberculosis DosS confers the unique sensitivity of DosS to oxygen.,Cho HY, Cho HJ, Kim MH, Kang BS FEBS Lett. 2011 Jun 23;585(12):1873-8. Epub 2011 Apr 27. PMID:21536032[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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