 |
PDBsum entry 1jhc
|
|
|
|
|
 |
Contents |
 |
|
|
|
|
|
|
|
|
|
|
* Residue conservation analysis
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Crystal structure of lexa: a conformational switch for regulation of self-Cleavage.
|
|
|
Authors
|
|
Y.Luo,
R.A.Pfuetzner,
S.Mosimann,
M.Paetzel,
E.A.Frey,
M.Cherney,
B.Kim,
J.W.Little,
N.C.Strynadka.
|
|
|
Ref.
|
|
Cell, 2001,
106,
585-594.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
LexA repressor undergoes a self-cleavage reaction. In vivo, this reaction
requires an activated form of RecA, but it occurs spontaneously in vitro at high
pH. Accordingly, LexA must both allow self-cleavage and yet prevent this
reaction in the absence of a stimulus. We have solved the crystal structures of
several mutant forms of LexA. Strikingly, two distinct conformations are
observed, one compatible with cleavage, and the other in which the cleavage site
is approximately 20 A from the catalytic center. Our analysis provides insight
into the structural and energetic features that modulate the interconversion
between these two forms and hence the rate of the self-cleavage reaction. We
suggest RecA activates the self-cleavage of LexA and related proteins through
selective stabilization of the cleavable conformation.
|
|
|
|
|
|
|
|
Figure 5.
Figure 5. Mapping of Previously Characterized MutantsA
stereo ribbon representation of LexA (C form) with LexA Ind^−
mutations (in blue), Ind^s mutations (in green), and λ cI
RecA-specific mutations (in brown) mapped on the structure (as
based on Figure 1)
|
|
Figure 6.
Figure 6. The Exposed Hydrophobic Surface of LexAThe
catalytic core of LexA is shown in a molecular surface
representation with the hydrophobic area highlighted in green
(GRASP; Honig and Nicholls, 1995). The CSR and linker loop are
shown as red and purple ribbons, respectively. The side chains
of selected hydrophobic side chains on the CSR that become
differentially exposed to solvent are highlighted in a cyan ball
and stick representation.(A) NC form.(B) C form
|
|
|
|
|
|
The above figures are
reprinted
by permission from Cell Press:
Cell
(2001,
106,
585-594)
copyright 2001.
|
|
|
|
|
|
|
