{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"submitter":["Juers DH"],"funding":["Howard Hughes Medical Institute","NIGMS NIH HHS"],"pagination":["1281-92"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC2774438"],"repository":["biostudies-literature"],"omics_type":["Unknown"],"volume":["18(6)"],"pubmed_abstract":["The active site of ss-galactosidase (E. coli) contains a Mg(2+) ion ligated by Glu-416, His-418 and Glu-461 plus three water molecules. A Na(+) ion binds nearby. To better understand the role of the active site Mg(2+) and its ligands, His-418 was substituted with Asn, Glu and Phe. The Asn-418 and Glu-418 variants could be crystallized and the structures were shown to be very similar to native enzyme. The Glu-418 variant showed increased mobility of some residues in the active site, which explains why the substitutions at the Mg(2+) site also reduce Na(+) binding affinity. The Phe variant had reduced stability, bound Mg(2+) weakly and could not be crystallized. All three variants have low catalytic activity due to large decreases in the degalactosylation rate. Large decreases in substrate b"],"journal":["Protein science : a publication of the Protein Society"],"pubmed_title":["Direct and indirect roles of His-418 in metal binding and in the activity of beta-galactosidase (E. coli)."],"pmcid":["PMC2774438"],"funding_grant_id":["GM 20066"],"pubmed_authors":["Rob B","Matthews BW","Dugdale ML","Rahimzadeh N","Lee M","Giang C","Juers DH","Huber RE"],"additional_accession":[]},"is_claimable":false,"name":"Direct and indirect roles of His-418 in metal binding and in the activity of beta-galactosidase (E. coli).","description":"The active site of ss-galactosidase (E. coli) contains a Mg(2+) ion ligated by Glu-416, His-418 and Glu-461 plus three water molecules. A Na(+) ion binds nearby. To better understand the role of the active site Mg(2+) and its ligands, His-418 was substituted with Asn, Glu and Phe. The Asn-418 and Glu-418 variants could be crystallized and the structures were shown to be very similar to native enzyme. The Glu-418 variant showed increased mobility of some residues in the active site, which explains why the substitutions at the Mg(2+) site also reduce Na(+) binding affinity. The Phe variant had reduced stability, bound Mg(2+) weakly and could not be crystallized. All three variants have low catalytic activity due to large decreases in the degalactosylation rate. Large decreases in substrate b","dates":{"release":"2009-01-01T00:00:00Z","publication":"2009 Jun","modification":"2025-04-19T23:53:19.738Z","creation":"2019-03-27T00:26:25Z"},"accession":"S-EPMC2774438","cross_references":{"pubmed":["19472413"],"doi":["10.1002/pro.140"]}}