Kissing G domains of MnmE monitored by X-ray crystallography and pulse electron paramagnetic resonance spectroscopy.

ABSTRACT: MnmE, which is involved in the modification of the wobble position of certain tRNAs, belongs to the expanding class of G proteins activated by nucleotide-dependent dimerization (GADs). Previous models suggested the protein to be a multidomain protein whose G domains contact each other in a nucleotide dependent manner. Here we employ a combined approach of X-ray crystallography and pulse electron paramagnetic resonance (EPR) spectroscopy to show that large domain movements are coupled to the G protein cycle of MnmE. The X-ray structures show MnmE to be a constitutive homodimer where the highly mobile G domains face each other in various orientations but are not in close contact as suggested by the GDP-AlF(x) structure of the isolated domains. Distance measurements by pulse double electron-e

SUBMITTER: Meyer S 

PROVIDER: S-EPMC2749940 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature