PDBsum entry 1u5i

Hydrolase

PDB id: 1u5i

Contents

Protein chains

625 a.a. *

176 a.a. *

Waters ×299

* Residue conservation analysis

PDB id:

1u5i

Name:

Hydrolase

Title:

Crystal structure analysis of rat m-calpain mutant lys10 thr

Structure:

Calpain 2, large [catalytic] subunit precursor. Chain: a. Synonym: m-calpain large subunit. Engineered: yes. Mutation: yes. Calpain small subunit 1. Chain: b. Fragment: residues 1-184. Synonym: m-calpain small subunit.

Source:

Rattus norvegicus. Norway rat. Organism_taxid: 10116. Expressed in: escherichia coli. Expression_system_taxid: 562. Expression_system_taxid: 562

Biol. unit:

Dimer (from PQS)

Resolution:

2.86Å R-factor: 0.196 R-free: 0.283

Authors:

C.M.Hosfield,G.P.Pal,J.S.Elce,Z.Jia

Key ref:

C.M.Hosfield et al. (2004). Activation of calpain by Ca2+: roles of the large subunit N-terminal and domain III-IV linker peptides. J Mol Biol, 343, 1049-1053. PubMed id: 15476820 DOI: 10.1016/j.jmb.2004.08.073

Date:

27-Jul-04 Release date: 18-Jan-05

Protein chain

Q07009  (CAN2_RAT) -  Calpain-2 catalytic subunit from Rattus norvegicus

Seq: 700 a.a.

Struc: 625 a.a.*

Protein chain

Q64537  (CPNS1_RAT) -  Calpain small subunit 1 from Rattus norvegicus

Seq: 270 a.a.

Struc: 176 a.a.

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Enzyme reactions

• Enzyme class 1: Chain A: E.C.3.4.22.53 - calpain-2.
• Cofactor: Ca(2+)
• Enzyme class 2: Chain B: E.C.?

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

DOI no: 10.1016/j.jmb.2004.08.073

J Mol Biol 343:1049-1053 (2004)

PubMed id: 15476820

Activation of calpain by Ca2+: roles of the large subunit N-terminal and domain III-IV linker peptides.

C.M.Hosfield, J.S.Elce, Z.Jia.

ABSTRACT

The calpains are a family of cysteine proteases with closely related amino acid sequences, but a wide range of Ca(2+) requirements (K(d)). For m-calpain, K(d) is approximately 325microM, for mu-calpain it is approximately 50microM, and for calpain 3 it is not strictly known but may be approximately 0.1microM. On the basis of previous structure determination of m-calpain we postulated that two regions of the calpain large subunits, the N-terminal peptide (residues 1-20) and a domain III-IV linker peptide (residues 514-530 in m-calpain) were important in defining K(d). The mutations Lys10Thr in the N-terminal peptide, and Glu517Pro in the domain linker peptide, reduced K(d) of m-calpain by 30% and 42%, respectively, revealing that these two regions are functionally important. The increased Ca(2+)-sensitivity of these mutants demonstrate that the Lys10-Asp148 salt link and the short beta-sheet interaction involving Glu517 are factors contributing to the high K(d) of m-calpain. Though these two regions are physically remote from the active site and Ca(2+)-binding site, they play significant roles in regulating the response of calpain to Ca(2+). Differences in these interactions in mu-calpain and in calpain 3 are also consistent with their progressively lower K(d) values.

Selected figure(s)

Figure 1.
Figure 1. Structure of Lys10Thr-m-calpain. Side-chains of relevant residues are shown. The two-strand b-sheet involving the domain III-IV linker peptide is highlighted in dark blue. The boxed area is amplified to illustrate that Asp148 and Thr10 are too far apart to form any interaction, in contrast to Asp148 and Lys10 in the wild-type protein where a double salt-bridge is formed. Domain/segment coloring scheme--D-I: dark blue; D-II: light blue; D-III: green; D-IV: yellow; D-VI: brown; N-terminal peptide: red; D-III/D-IV linker: purple.

The above figure is reprinted by permission from Elsevier: J Mol Biol (2004, 343, 1049-1053) copyright 2004.