PDBsum entry 4g4e

Hydrolase

PDB id: 4g4e

Contents

Protein chains

(+ 6 more) 169 a.a.

PDB id:

4g4e

Name:

Hydrolase

Title:

Crystal structure of the l88a mutant of hslv from escherichia coli

Structure:

Atp-dependent protease subunit hslv. Chain: a, b, c, d, e, f, g, h, i, j, k, l. Synonym: heat shock protein hslv. Engineered: yes. Mutation: yes

Source:

Escherichia coli. Organism_taxid: 83333. Strain: k12. Gene: hslv. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.89Å R-factor: 0.259 R-free: 0.293

Authors:

J.W.Lee,E.Park,H.M.Yoo,B.H.Ha,J.Y.An,Y.J.Jeon,J.H.Seol,S.H.Eom, C.H.Chung

Key ref:

E.Park et al. (2013). Structural alteration in the pore motif of the bacterial 20S proteasome homolog HslV leads to uncontrolled protein degradation. J Mol Biol, 425, 2940-2954. PubMed id: 23707406 DOI: 10.1016/j.jmb.2013.05.011

Date:

16-Jul-12 Release date: 12-Jun-13

Protein chains

P0A7B8  (HSLV_ECOLI) -  ATP-dependent protease subunit HslV from Escherichia coli (strain K12)

Seq: 176 a.a.

Struc: 169 a.a.

Enzyme reactions

• Enzyme class: E.C.3.4.25.2 - HslU--HslV peptidase.

DOI no: 10.1016/j.jmb.2013.05.011

J Mol Biol 425:2940-2954 (2013)

PubMed id: 23707406

Structural alteration in the pore motif of the bacterial 20S proteasome homolog HslV leads to uncontrolled protein degradation.

E.Park, J.W.Lee, H.M.Yoo, B.H.Ha, J.Y.An, Y.J.Jeon, J.H.Seol, S.H.Eom, C.H.Chung.

ABSTRACT

In all cells, ATP-dependent proteases play central roles in the controlled degradation of short-lived regulatory or misfolded proteins. A hallmark of these enzymes is that proteolytic active sites are sequestered within a compartmentalized space, which is accessible to substrates only when they are fed into the cavity by protein-unfolding ATPases. HslVU is a prototype of such enzymes, consisting of the hexameric HslU ATPase and the dodecameric HslV protease. HslV forms a barrel-shaped proteolytic chamber with two constricted axial pores. Here, we report that structural alterations of HslV's pore motif dramatically affect the proteolytic activities of both HslV and HslVU complexes. Mutations of a conserved pore residue in HslV (Leu88 to Ala, Gly, or Ser) led to a tighter binding between HslV and HslU and a dramatic stimulation of both the proteolytic and ATPase activities. Furthermore, the HslV mutants alone showed a marked increase of basal hydrolytic activities toward small peptides and unstructured proteins. A synthetic peptide of the HslU C-terminal tail further stimulated the proteolytic activities of these mutants, even allowing degradation of certain folded proteins in the absence of HslU. Moreover, expression of the L88A mutant in Escherichia coli inhibited cell growth, suggesting that HslV pore mutations dysregulate the protease through relaxing the pore constriction, which normally prevents essential cellular proteins from random degradation. Consistent with these observations, an X-ray crystal structure shows that the pore loop of L88A-HslV is largely disordered. Collectively, these results suggest that substrate degradation by HslV is controlled by gating of its pores.