Format

Send to

Choose Destination
Structure. 2008 Aug 6;16(8):1157-65. doi: 10.1016/j.str.2008.04.016.

Synchrotron protein footprinting supports substrate translocation by ClpA via ATP-induced movements of the D2 loop.

Author information

1
Center for Proteomics and Center for Synchrotron Biosciences, Case Western Reserve University, Cleveland, OH 44106, USA.

Abstract

Synchrotron X-ray protein footprinting is used to study structural changes upon formation of the ClpA hexamer. Comparative solvent accessibilities between ClpA monomer and ClpA hexamer samples are in agreement throughout most of the sequence, with calculations based on two previously proposed hexameric models. The data differ substantially from the proposed models in two parts of the structure: the D1 sensor 1 domain and the D2 loop region. The results suggest that these two regions can access alternate conformations in which their solvent protection is greater than that in the structural models based on crystallographic data. In combination with previously reported structural data, the footprinting data provide support for a revised model in which the D2 loop contacts the D1 sensor 1 domain in the ATP-bound form of the complex. These data provide the first direct experimental support for the nucleotide-dependent D2 loop conformational change previously proposed to mediate substrate translocation.

PMID:
18682217
PMCID:
PMC2929679
DOI:
10.1016/j.str.2008.04.016
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center