Linked Life Data

11524417

Source:http://linkedlifedata.com/resource/pubmed/id/11524417

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
47
pubmed:dateCreated
2001-11-19
pubmed:databankReference
pubmed:abstractText
The enzymatic catalysis of many biological processes of life is supported by the presence of cofactors and prosthetic groups originating from the common tetrapyrrole precursor uroporphyrinogen-III. Uroporphyrinogen-III decarboxylase catalyzes its conversion into coproporphyrinogen-III, leading in plants to chlorophyll and heme biosynthesis. Here we report the first crystal structure of a plant (Nicotiana tabacum) uroporphyrinogen-III decarboxylase, together with the molecular modeling of substrate binding in tobacco and human enzymes. Its structural comparison with the homologous human protein reveals a similar catalytic cleft with six invariant polar residues, Arg(32), Arg(36), Asp(82), Ser(214) (Thr in Escherichia coli), Tyr(159), and His(329) (tobacco numbering). The functional relationships obtained from the structural and modeling analyses of both enzymes allowed the proposal for a refined catalytic mechanism. Asp(82) and Tyr(159) seem to be the catalytic functional groups, whereas the other residues may serve in substrate recognition and binding, with Arg(32) steering its insertion. The crystallographic dimer appears to represent the protein dimer under physiological conditions. The dimeric arrangement offers a plausible mechanism at least for the first two (out of four) decarboxylation steps.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
44108-16
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Crystal structure and substrate binding modeling of the uroporphyrinogen-III decarboxylase from Nicotiana tabacum. Implications for the catalytic mechanism.
pubmed:affiliation
Max-Planck-Institut für Biochemie, Abteilung Strukturforschung, Am Klopferspitz 18a, 82152 Martinsried bei München, Germany. martins@biochem.mpg.de
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't