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Structural analysis of the first GAF domain from Mycobacterium tuberculosis Rv3132c (DosS) protein
Author(s) -
CHO HA YEON,
CHO HYO JE,
KANG BEOM SIK
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.874.1
Subject(s) - crystallography , chemistry , ferrous , christian ministry , stereochemistry , organic chemistry , theology , philosophy
DosS‐DosR is a two‐component regulatory system for hypoxia sensing in Mycobacterium tuberculosis and DosS is a sensor histidine kinase. The N‐terminal sensory domain of DosS contains two GAF domains. Here, we determined the molecular structure of the first GAF domain (GAF‐A) by X‐ray crystallography in order to give a hint for the sensing mechanism. The crystal GAF‐A obtained by sitting‐drop vapor diffusion method in the condition of 0.2M calcium acetate, 18% polyethylene glycol 6000K. The GAF‐A consisted of a central five‐stranded anti‐parallel β‐sheets, and four α‐helices. The N‐and C‐terminal helices are at one side of the sheet and a mixture of long loops and two helices at the other side. A b‐type heme was found in a cavity between the β‐sheets and the loops. UV‐visible spectroscopic and X‐ray crystallographic analysis revealed that the heme of ferric form is a six‐coordinated state and upon its reduction, it is converted to a five‐coordinated ferrous form. Cyanide complex form of GAF‐A suggests its diatomic ligand binding.[Grant sponsor: 21C Frontier Microbial Genomics and Application Center Program, Ministry of Science and Technology, Republic of Korea]