2PKC

Crystal structure of calcium-free proteinase K at 1.5-A resolution.

(1994) J Biol Chem 269: 23108-23111

• PubMed: 8083213 Search on PubMed
• DOI: https://doi.org/10.2210/pdb2pkc/pdb
• Primary Citation of Related Structures:  
  2PKC


• PubMed Abstract: 
  

  Proteinase K from the fungus Tritirachium album Limber binds two Ca2+ ions, one strongly (Ca 1) and the other weakly (Ca 2). Removal of these cations reduces the stability of proteinase K as shown by thermal denaturation, but the proteolytic activity is unchanged. The x-ray structures of native and Ca(2+)-free proteinase K at 1.5-A resolution show that there are no cuts in the polypeptide backbone (i.e. no autolysis), Ca 1 has been replaced by Na+, while Ca 2 has been substituted by a water associated with a larger but locally confined structural change at that site. A small but concerted geometrical shift is transmitted from the Ca 1 site via eight secondary structure elements to the substrate recognition site (Gly100-Tyr104, and Ser132-Gly136) but not to the catalytic triad (Asp39,His69,Ser224). This is accompanied by positional changes of localized waters.

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Organizational Affiliation: 

Institut für Kristallographie, Freie Universität Berlin, Federal Republic of Germany.