Structural insights into conserved l‐arabinose metabolic enzymes reveal the substrate binding site of a thermophilic l‐arabinose isomerase

摘要

Structuralgenomicsdemonstratesthatdespitelowlevelsofstructuralsimilarityofproteinscomprisingametabolicpathway,theirsubstratebindingregionsarelikelytobeconserved.Hereinbasedonthe3D‐structuresoftheα/β‐foldproteinsinvolvedinthearaoperon,weattemptedtopredictthesubstratebindingresiduesofthermophilicGeobacillusstearothermophilusl‐arabinoseisomerase(GSAI)withno3D‐structureavailable.Comparisonofthestructuresofl‐arabinosecatabolicenzymesrevealedaconservedfeaturetoformthesubstrate‐bindingmodules,whichcanbeextendedtopredictthesubstratebindingsiteofGSAI(i.e.,D195,E261andE333).Moreover,thesedataimplicatedthatproteinsinthel‐arabinosemetabolicpathwaymightretaintheirsubstratebindingnichesasthemodularstructurethroughconservedmolecularevolutionevenwithtotallydifferentstructuralscaffolds...