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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6002
pubmed:dateCreated
1985-3-19
pubmed:abstractText
Glycogen phosphorylase (E.C.2.4.1.1) was the first enzyme shown to be regulated by allosteric effectors and by protein phosphorylation. Transcriptional control of bacterial phosphorylases further extends the range of regulatory mechanisms by which phosphorylases contribute to the control of carbohydrate metabolism. Despite their regulatory differences, all known phosphorylases share catalytic and structural properties and a strongly conserved pyridoxal-5'-phosphate binding site; this makes phosphorylases highly attractive for investigations into the evolution of regulatory mechanisms. The primary and tertiary structure of rabbit muscle phosphorylase has been determined completely. Recently, comparable amino acid sequences from plants and bacteria have been resolved. Here we report the sequence of 687 amino acids of Escherichia coli maltodextrin phosphorylase, deduced from a cloned malP gene sequence. Alignment of animal and bacterial phosphorylase sequences shows strong homology (48%) throughout 91% of the polypeptide chain enclosing the extrinsic catalytic region. Within this region, structural homology identifies a presumed phosphate-binding site from which the allosteric 5' AMP binding site of rabbit muscle phosphorylase might have developed. From the decreased alignment at the N-terminus and the presence of additional residues compared with bacterial phosphorylases, we conclude that the regulatory sequences that also carry the phosphorylation site in the muscle enzyme were joined to a presumed ancestral precursor gene by gene fusion after separation of the eukaryotic and prokaryotic lines of descent.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0028-0836
pubmed:author
pubmed:issnType
Print
pubmed:volume
313
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
500-2
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:articleTitle
Evolution of catalytic and regulatory sites in phosphorylases.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't