Linked Life Data

15136045

Source:http://linkedlifedata.com/resource/pubmed/id/15136045

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2004-5-11
pubmed:databankReference
pubmed:abstractText
In order to understand the structural basis for the high thermostability of phytase from Aspergillus fumigatus, its crystal structure was determined at 1.5 A resolution. The overall fold resembles the structure of other phytase enzymes. Aspergillus niger phytase shares 66% sequence identity, however, it is much less heat-resistant. A superimposition of these two structures reveals some significant differences. In particular, substitutions with polar residues appear to remove repulsive ion pair interactions and instead form hydrogen bond interactions, which stabilize the enzyme; the formation of a C-terminal helical capping, induced by arginine residue substitutions also appears to be critical for the enzyme's ability to refold to its active form after denaturation at high temperature. The heat-resilient property of A.fumigatus phytase could be due to the improved stability of regions that are critical for the refolding of the protein; and a heat-resistant A.niger phytase may be achieved by mutating certain critical residues with the equivalent residues in A.fumigatus phytase. Six predicted N-glycosylation sites were observed to be glycosylated from the experimental electron density. Furthermore, the enzyme's catalytic residue His59 was found to be partly phosphorylated and thus showed a reaction intermediate, providing structural insight, which may help understand the catalytic mechanism of the acid phosphatase family. The trap of this catalytic intermediate confirms the two-step catalytic mechanism of the acid histidine phosphatase family.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
339
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
437-45
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Crystal structure of a heat-resilient phytase from Aspergillus fumigatus, carrying a phosphorylated histidine.
pubmed:affiliation
Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't