PDBsum entry 1jhe

Hydrolase

PDB id: 1jhe

Contents

Protein chains

124 a.a. *

Waters ×17

* Residue conservation analysis

PDB id:

1jhe

Name:

Hydrolase

Title:

Lexa l89p q92w e152a k156a mutant

Structure:

Lexa repressor. Chain: a, b. Fragment: c-terminus, residues 68-202. Engineered: yes. Mutation: yes

Source:

Escherichia coli. Organism_taxid: 562. Gene: lexa. Expressed in: escherichia coli. Expression_system_taxid: 562

Biol. unit:

Tetramer (from PQS)

Resolution:

2.50Å R-factor: 0.220 R-free: 0.284

Authors:

Y.Luo,R.A.Pfuetzner,S.Mosimann,J.W.Little,N.C.J Strynadka

Key ref:

Y.Luo et al. (2001). Crystal structure of LexA: a conformational switch for regulation of self-cleavage. Cell, 106, 585-594. PubMed id: 11551506 DOI: 10.1016/S0092-8674(01)00479-2

Date:

27-Jun-01 Release date: 19-Sep-01

Protein chains

P0A7C2  (LEXA_ECOLI) -  LexA repressor from Escherichia coli (strain K12)

Seq: 202 a.a.

Struc: 124 a.a.*

* PDB and UniProt seqs differ at 4 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.4.21.88 - repressor LexA.
• Reaction: Hydrolysis of Ala-|-Gly bond in repressor lexA.

DOI no: 10.1016/S0092-8674(01)00479-2

Cell 106:585-594 (2001)

PubMed id: 11551506

Crystal structure of LexA: a conformational switch for regulation of self-cleavage.

Y.Luo, R.A.Pfuetzner, S.Mosimann, M.Paetzel, E.A.Frey, M.Cherney, B.Kim, J.W.Little, N.C.Strynadka.

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.

Selected figure(s)

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.

Figures were selected by an automated process.