Document Detail

The crystal structure of 5'-deoxy-5'-methylthioadenosine phosphorylase II from Sulfolobus solfataricus, a thermophilic enzyme stabilized by intramolecular disulfide bonds.
MedLine Citation:
PMID:  16414070     Owner:  NLM     Status:  MEDLINE    
The crystal structure of Sulfolobus solfataricus 5'-deoxy-5'-methylthioadenosine phosphorylase II (SsMTAPII) in complex with 5'-deoxy-5'-methylthioadenosine (MTA) and sulfate was determined to 1.45A resolution. The hexameric structure of SsMTAPII is a dimer-of-trimers with one active site per monomer. The oligomeric assembly of the trimer and the monomer topology of SsMTAPII are almost identical with trimeric human 5'-deoxy-5'-methylthioadenosine phosphorylase (hMTAP). SsMTAPII is the first reported hexameric member in the trimeric class of purine nucleoside phosphorylase (PNP) from Archaea. Unlike hMTAP, which is highly specific for MTA, SsMTAPII also accepts adenosine as a substrate. The residues at the active sites of SsMTAPII and hMTAP are almost identical. The broad substrate specificity of SsMTAPII may be due to the flexibility of the C-terminal loop. SsMTAPII is extremely thermoactive and thermostable. The three-dimensional structure of SsMTAPII suggests that the unique dimer-of-trimers quaternary structure, a CXC motif at the C terminus, and two pairs of intrasubunit disulfide bridges may play an important role in its thermal stability.
Yan Zhang; Marina Porcelli; Giovanna Cacciapuoti; Steven E Ealick
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2005-12-27
Journal Detail:
Title:  Journal of molecular biology     Volume:  357     ISSN:  0022-2836     ISO Abbreviation:  J. Mol. Biol.     Publication Date:  2006 Mar 
Date Detail:
Created Date:  2006-03-13     Completed Date:  2006-04-18     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  2985088R     Medline TA:  J Mol Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  252-62     Citation Subset:  IM    
Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853-1301, USA.
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MeSH Terms
Binding Sites
Crystallography, X-Ray
Deoxyadenosines / chemistry
Disulfides / chemistry*
Enzyme Stability
Isoenzymes / chemistry*,  genetics
Models, Molecular
Molecular Sequence Data
Molecular Structure
Protein Structure, Quaternary*
Protein Subunits / chemistry,  genetics
Purine-Nucleoside Phosphorylase / chemistry*,  genetics
Substrate Specificity
Sulfolobus solfataricus / enzymology*
Thionucleosides / chemistry
Grant Support
Reg. No./Substance:
0/Deoxyadenosines; 0/Disulfides; 0/Isoenzymes; 0/Protein Subunits; 0/Thionucleosides; 2457-80-9/5'-methylthioadenosine; EC Phosphorylase; EC'-methylthioadenosine phosphorylase

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