1U5I

Crystal Structure analysis of rat m-calpain mutant Lys10 Thr

Summary for 1U5I

• Entry DOI: 10.2210/pdb1u5i/pdb
• Related: 1DF0 1QXP
• Descriptor: Calpain 2, large [catalytic] subunit precursor, Calpain small subunit 1 (3 entities in total)
• Functional Keywords: calpain, sulfhydryl protease, hydrolase
• Biological source: Rattus norvegicus (Norway rat); More
• Cellular location: Cytoplasm (By similarity): Q07009; Cytoplasm: Q64537
• Total number of polymer chains: 2
• Total formula weight: 101270.94

Authors

Hosfield, C.M.,Pal, G.P.,Elce, J.S.,Jia, Z. (deposition date: 2004-07-27, release date: 2005-01-18, Last modification date: 2024-05-29)

Primary citation

Hosfield, C.M.,Elce, J.S.,Jia, Z.
Activation of calpain by Ca2+: roles of the large subunit N-terminal and domain III-IV linker peptides
J.Mol.Biol., 343:1049-1053, 2004

PubMed 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.

PubMed: 15476820
DOI: 10.1016/j.jmb.2004.08.073

Experimental method

X-RAY DIFFRACTION (2.86 Å)