Grandes complexos de proteínas revelam grande diversidade estrutural

sábado, setembro 12, 2009

Survey of large protein complexes in D. vulgaris reveals great structural diversity

Bong-Gyoon Hana,1, Ming Dongb,1, Haichuan Liuc, Lauren Campd, Jil Gellerd, Mary Singerd, Terry C. Hazend, Megan Choib, H. Ewa Witkowskac, David A. Balla, Dieter Typkea, Kenneth H. Downinga, Maxim Shatskye,f, Steven E. Brennere,f, John-Marc Chandoniae,f, Mark D. Bigginb and Robert M. Glaesera,f,2

+ Author Affiliations

aLife Sciences,

bGenomics,

dEarth Sciences, and

fPhysical Biosciences Divisions, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720;

cOB/GYN Department, University of California San Fransisco Sandler-Moore Mass Spectrometry Core Facility, University of California, San Francisco, CA 94143; and

eDepartment of Plant and Microbial Biology, University of California, Berkeley, CA 94720

Edited by David S. Eisenberg, University of California, Los Angeles, CA, and approved August 17, 2009

↵1B.-G.H. and M.D. contributed equally to this work. (received for review January 3, 2009)

Abstract

An unbiased survey has been made of the stable, most abundant multi-protein complexes in Desulfovibrio vulgaris Hildenborough (DvH) that are larger than Mr ≈ 400 k. The quaternary structures for 8 of the 16 complexes purified during this work were determined by single-particle reconstruction of negatively stained specimens, a success rate ≈10 times greater than that of previous “proteomic” screens. In addition, the subunit compositions and stoichiometries of the remaining complexes were determined by biochemical methods. Our data show that the structures of only two of these large complexes, out of the 13 in this set that have recognizable functions, can be modeled with confidence based on the structures of known homologs. These results indicate that there is significantly greater variability in the way that homologous prokaryotic macromolecular complexes are assembled than has generally been appreciated. As a consequence, we suggest that relying solely on previously determined quaternary structures for homologous proteins may not be sufficient to properly understand their role in another cell of interest.

comparative evolutionary analysis single-particle electron microscopy structural homology
Footnotes

2To whom correspondence should be addressed. E-mail: rmglaeser@lbl.gov

Author contributions: B.-G.H., M.D., T.C.H., H.E.W., K.H.D., S.E.B., J.-M.C., M.D.B., and R.M.G. designed research; B.-G.H., M.D., H.L., L.C., J.G., M. Singer, M.C., D.A.B., D.T., and M. Shatsky performed research; B.-G.H., M.D., H.L., H.E.W., D.A.B., M. Shatsky, S.E.B., and J.-M.C. analyzed data; and M.D., T.C.H., H.E.W., D.A.B., K.H.D., M. Shatsky, S.E.B., J.-M.C., M.D.B., and R.M.G. wrote the paper.

The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

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