TY - JOUR
T1 - Molecular recognition of an ADP-ribosylating Clostridium botulinum C3 exoenzyme by RalA GTPase
AU - Holbourn, Kenneth P.
AU - Sutton, J. Mark
AU - Evans, Hazel R.
AU - Shone, Clifford
AU - Acharya, K. Ravi
PY - 2005/4/12
Y1 - 2005/4/12
N2 - C3 exoenzymes (members of the ADP-ribosyltranferase family) are produced by Clostridium botulinum (C3bot1 and -2), Clostridium limosum (C3lim), Bacillus cereus (C3cer), and Staphylococcus aureus (C3stau1-3). These exoenzymes lack a translocation domain but are known to specifically inactivate Rho GTPases in host target cells. Here, we report the crystal structure of C3bot1 in complex with RalA (a GTPase of the Ras subfamily) and GDP at a resolution of 2.66 Å. RalA is not ADP-ribosylated by C3 exoenzymes but inhibits ADP-ribosylation of RhoA by C3bot1, C3lim, and C3cer to different extents. The structure provides an insight into the molecular interactions between C3bot1 and RalA involving the catalytic ADP-ribosylating turn-turn (ARTT) loop from C3bot1 and helix α4 and strand β6 (which are not part of the GDP-binding pocket) from RalA. The structure also suggests a molecular explanation for the different levels of C3-exoenzyme inhibition by RalA and why RhoA does not bind C3bot1 in this manner.
AB - C3 exoenzymes (members of the ADP-ribosyltranferase family) are produced by Clostridium botulinum (C3bot1 and -2), Clostridium limosum (C3lim), Bacillus cereus (C3cer), and Staphylococcus aureus (C3stau1-3). These exoenzymes lack a translocation domain but are known to specifically inactivate Rho GTPases in host target cells. Here, we report the crystal structure of C3bot1 in complex with RalA (a GTPase of the Ras subfamily) and GDP at a resolution of 2.66 Å. RalA is not ADP-ribosylated by C3 exoenzymes but inhibits ADP-ribosylation of RhoA by C3bot1, C3lim, and C3cer to different extents. The structure provides an insight into the molecular interactions between C3bot1 and RalA involving the catalytic ADP-ribosylating turn-turn (ARTT) loop from C3bot1 and helix α4 and strand β6 (which are not part of the GDP-binding pocket) from RalA. The structure also suggests a molecular explanation for the different levels of C3-exoenzyme inhibition by RalA and why RhoA does not bind C3bot1 in this manner.
KW - ADP-ribosylation
KW - Protein-protein interaction
KW - X-ray crystallography
UR - http://www.scopus.com/inward/record.url?scp=17244365578&partnerID=8YFLogxK
U2 - 10.1073/pnas.0501525102
DO - 10.1073/pnas.0501525102
M3 - Article
C2 - 15809419
AN - SCOPUS:17244365578
SN - 0027-8424
VL - 102
SP - 5357
EP - 5362
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 15
ER -