Linked Life Data

12122021

Source:http://linkedlifedata.com/resource/pubmed/id/12122021

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2002-7-17
pubmed:abstractText
The catalytic domain of bovine beta1,4-galactosyltransferase (beta4Gal-T1) has been shown to have two metal binding sites, each with a distinct binding affinity. Site I binds Mn(2+) with high affinity and does not bind Ca(2+), whereas site II binds a variety of metal ions, including Ca(2+). The catalytic region of beta4Gal-T1 has DXD motifs, associated with metal binding in glycosyltransferases, in two separate sequences: D(242)YDYNCFVFSDVD(254) (region I) and W(312)GWGGEDDD(320) (region II). Recently, the crystal structure of beta4Gal-T1 bound with UDP, Mn(2+), and alpha-lactalbumin was determined in our laboratory. It shows that in the primary metal binding site of beta4Gal-T1, the Mn(2+) ion, is coordinated to five ligands, two supplied by the phosphates of the sugar nucleotide and the other three by Asp254, His347, and Met344. The residue Asp254 in the D(252)VD(254) sequence in region I is the only residue that is coordinated to the Mn(2+) ion. Region II forms a loop structure and contains the E(317)DDD(320) sequence in which residues Asp318 and Asp319 are directly involved in GlcNAc binding. This study, using site-directed mutagenesis, kinetic, and binding affinity analysis, shows that Asp254 and His347 are strong metal ligands, whereas Met344, which coordinates less strongly, can be substituted by alanine or glutamine. Specifically, substitution of Met344 to Gln has a less severe effect on the catalysis driven by Co(2+). Glu317 and Asp320 mutants, when partially activated by Mn(2+) binding to the primary site, can be further activated by Co(2+) or inhibited by Ca(2+), an effect that is the opposite of what is observed with the wild-type enzyme.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0959-6658
pubmed:author
pubmed:issnType
Print
pubmed:volume
12
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
395-407
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Studies on the metal binding sites in the catalytic domain of beta1,4-galactosyltransferase.
pubmed:affiliation
Structural Glycobiology Section and Intramural Research Support Program-SAIC, Laboratory of Experimental and Computational Biology, NCI-CCR, Building 469, Room 221, Frederick, MD 21702-1201, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.