PDBsum entry 1qxp

Hydrolase chimera

PDB id: 1qxp

Contents

Protein chains

783 a.a. *

788 a.a. *

Waters ×312

* Residue conservation analysis

PDB id:

1qxp

Name:

Hydrolase chimera

Title:

Crystal structure of a mu-like calpain

Structure:

Mu-like calpain. Chain: a, b. Engineered: yes. Mutation: yes. Other_details: residues 1-49 from m-calpain, residues 60-647 of mu- calpain, residues 636-700 of m-calpain and residues 83-266 of calcium-activated neutral proteinase.

Source:

Rattus norvegicus, bos taurus. Norway rat, cattle. Organism_taxid: 10116, 9913. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.80Å R-factor: 0.233 R-free: 0.311

Authors:

G.P.Pal,T.D.Veyra,J.S.Elce,Z.Jia

Key ref:

G.P.Pal et al. (2003). Crystal structure of a micro-like calpain reveals a partially activated conformation with low Ca2+ requirement. Structure, 11, 1521-1526. PubMed id: 14656436 DOI: 10.1016/j.str.2003.11.007

Date:

08-Sep-03 Release date: 03-Feb-04

Protein chain

P97571  (CAN1_RAT) -  Calpain-1 catalytic subunit from Rattus norvegicus

Seq: 713 a.a.

Struc: 783 a.a.*

Protein chain

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

Seq: 700 a.a.

Struc: 783 a.a.*

Protein chain

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

Seq: 270 a.a.

Struc: 783 a.a.*

Protein chain

P97571  (CAN1_RAT) -  Calpain-1 catalytic subunit from Rattus norvegicus

Seq: 713 a.a.

Struc: 788 a.a.*

Protein chain

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

Seq: 700 a.a.

Struc: 788 a.a.*

Protein chain

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

Seq: 270 a.a.

Struc: 788 a.a.*

* PDB and UniProt seqs differ at 663 residue positions (black crosses)

Enzyme reactions

• Enzyme class 1: Chains A, B: E.C.3.4.22.52 - calpain-1.
• Cofactor: Ca(2+)
• Enzyme class 2: Chains A, B: E.C.3.4.22.53 - calpain-2.
• Cofactor: Ca(2+)

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.str.2003.11.007

Structure 11:1521-1526 (2003)

PubMed id: 14656436

Crystal structure of a micro-like calpain reveals a partially activated conformation with low Ca2+ requirement.

G.P.Pal, T.De Veyra, J.S.Elce, Z.Jia.

ABSTRACT

The two Ca2+-dependent cysteine proteases, micro- and m-calpain, are involved in various Ca2+-linked signal pathways but differ markedly in their Ca2+ requirements for activation. We have determined the structure of a micro-like calpain, which has 85% micro-calpain sequence (the first 48 and the last 62 residues of the large subunit are those from m-calpain) and a low Ca2+ requirement. This construct was used because micro-calpain itself is too poorly expressed. The structure of micro-like calpain is very similar in overall fold to that of m-calpain as expected, but differs significantly in two aspects. In comparison with m-calpain, the catalytic triad residues in micro-like calpain, His and Cys, are much closer together in the absence of Ca2+, and significant portions of the Ca2+ binding EF-hand motifs are disordered and more flexible. These structural differences imply that Ca2+-free micro-calpain may represent a partially activated structure, requiring lower Ca2+ concentration to trigger its activation.

Selected figure(s)

Figure 2.
Figure 2. A Section of the Electron Density Map in which the Catalytic Residue His262 Is Shown to Be Well Defined and Stacked with Trp288The map is contoured at 1 s.

The above figure is reprinted by permission from Cell Press: Structure (2003, 11, 1521-1526) copyright 2003.

Figure was selected by an automated process.