ARS | Publication request: Atypical Structural Features of Two MAP P60 Family Members

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 9, 2009
Publication Date: August 9, 2009
Citation: Ramyar, K.X., Lingle, C.K., Mcwhorter, W.J., Bouyain, S., Bannantine, J.P., Geisbrecht, B.V. 2009. Atypical Structural Features of Two MAP P60 Family Members [abstract].

Technical Abstract: The majority of Map gene products have no known function. In order to better understand the pathobiology of this mycobacterium, we have begun to study the structure-function relationship of a subset of Map proteins. We have selected a number of gene products unique to Map, which are either predicted to be secreted or expressed on the surface of the mycobacterium. Here we report the atomic resolution crystal structures of two Map proteins, 1272c and 1204. Both proteins are members of the NlpC/P60 superfamily of peptidylglycan hydrolases and are predicted to be expressed on the surface of the bacteria. Surprisingly, neither protein appears to have a functional catalytic core. It is clear from the structure of 1272c that the residues required for hydrolysis are absent, strongly suggesting a role as a binding protein or receptor for this protein. While the Cys-His-Glu catalytic triad is present in 1204, other residues occlude access to the catalytic site. Based on these two structures, and a thorough search of the Map genome, we can conclude that the canonical role of a peptidylglycan hydrolase is not fulfilled by either 1204 or 1272c. As both these proteins are strongly recognized by antibodies from infected animals, we propose that they function in an as yet undetermined role during pathogenesis.