BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Three-dimensional electron microscopy and molecular modelling stud
 ies of a spiral-forming biocatalyst
DTSTART;VALUE=DATE-TIME:20110714T103000Z
DTEND;VALUE=DATE-TIME:20110714T104500Z
DTSTAMP;VALUE=DATE-TIME:20260811T043714Z
UID:indico-contribution-5112@events.saip.org.za
DESCRIPTION:Speakers: Jean Watermeyer (University of Cape Town)\nNitrilase
  and amidase enzymes catalyse the conversion of nitriles and amides to the
 ir corresponding acid and ammonia - chemistry which is useful in synthesis
  of drug compounds and fine chemicals.  The conversion of cyanide\, a nitr
 ile\, to ammonia and formic acid is useful in detoxification of contaminat
 ed wastewater.  The cyanide dihydratase from Bacillus pumilus (CynDpum) ca
 talyses this reaction and is thus a potentially useful biocatalyst.  CynDp
 um and related nitrilase enzymes become activated by formation of spiral-s
 haped multimers.  Evidence suggests that multimer formation regulates acti
 vity\, by mechanisms which are still not clear.  We have used a combinatio
 n of transmission electron microscopy (EM) with 3-D image reconstruction\,
  molecular modelling\, and mutagenesis to investigate the mechanism of hel
 ix formation in CynDpum.  We have implemented a new routine in the molecul
 ar dynamics package\, NAMD\, that allows helical symmetry to be used as a 
 constraint\, together with the EM volume.  This method improves on asymmet
 rical modelling procedures and has aided in our atomic-level interpretatio
 n of low-resolution 3-D maps from negative-stain EM.  This in turn has all
 owed us to make testable predictions about the importance of specific amin
 o acids for the mechanical stability of the spirals.  We show that salt br
 idges in one interface are not required for complex formation\, but that m
 utations in this area can enhance the mechanical stability of the enzyme.\
 n\nhttps://events.saip.org.za/event/7/contributions/5112/
LOCATION: Acro3
URL:https://events.saip.org.za/event/7/contributions/5112/
END:VEVENT
END:VCALENDAR