Open AccessC3 exoenzyme from Clostridium botulinum : structure of a tetragonal crystal form and a reassessment of NAD‐induced flexure
Author(s) -
Evans Hazel R.,
Holloway Daniel E.,
Sutton J. Mark,
Ayriss Joanne,
Shone Clifford C.,
Acharya K. Ravi
Publication year - 2004
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
ISSN - 1399-0047
DOI - 10.1107/s0907444904011680
Subject(s) - exoenzyme , tetragonal crystal system , nad+ kinase , monoclinic crystal system , crystal (programming language) , clostridium botulinum , crystallography , crystal structure , dimer , chemistry , stereochemistry , biochemistry , enzyme , toxin , organic chemistry , computer science , programming language
C3 exoenzyme from Clostridium botulinum (C3bot1) ADP‐ribosylates and thereby inactivates Rho A, B and C GTPases in mammalian cells. The structure of a tetragonal crystal form has been determined by molecular replacement and refined to 1.89 Å resolution. It is very similar to the apo structures determined previously from two different monoclinic crystal forms. An objective reassessment of available apo and nucleotide‐bound C3bot1 structures indicates that, contrary to a previous report, the protein possesses a rigid core formed largely of β‐strands and that the general flexure that accompanies NAD binding is concentrated in two peripheral lobes. Tetragonal crystals disintegrate in the presence of NAD, most likely because of disruption of essential crystal contacts.