In our case, the Ca ion is essential for activity but not correct folding. The enzyme requires Ca2+ (Mg or Mn) for activity. The crystal structure shows a single Ca2+ ion coordinated by a key catalytic aspartate and two backbone carbonyls. Mutagenesis of the key Asparate abolishes enzyme activity, and the presence of the Ca2+ ion in the structure.
________________________________________ From: Eleanor Dodson [[email protected]] Sent: 31 May 2013 12:49 To: RHYS GRINTER Cc: [email protected] Subject: Re: [ccp4bb] Calcium ions in enzymes I would think a Google search would make some suggestions for you. There are lots of cases of proteins which require Calcium to function, but it is a bit chicken-and-egg-y - can the protein only function after it folds correctly, and is the Ca essential for that folding? On 31 May 2013 11:54, RHYS GRINTER <[email protected]<mailto:[email protected]>> wrote: My work with colicin M class bacteriocins shows that they require Ca2+ (or Mg or Mn) for catalysis: 1 Grinter, R., Roszak, A. W., Cogdell, R. J., Milner, J. J. and Walker, D. (2012) The Crystal Structure of the Lipid II-degrading Bacteriocin Syringacin M Suggests Unexpected Evolutionary Relationships between Colicin M-like Bacteriocins. J. Biol. Chem. 287, 38876-38888 Best Regards, Rhys ________________________________________ From: CCP4 bulletin board [[email protected]<mailto:[email protected]>] On Behalf Of Wei Liu [[email protected]<mailto:[email protected]>] Sent: 31 May 2013 11:25 To: [email protected]<mailto:[email protected]> Subject: [ccp4bb] Calcium ions in enzymes Dear all, As we all know, many proteins contain calcium ions. Does anyone know if there are reported cases where calcium ions play a catalytic role rather than a structural role in enzymes? Best Wei Liu
