{"title":"Phylogenetic analyses of proton-translocating transhydrogenases.","authors":"W K Studley, M Yamaguchi, Y Hatefi, M H Saier","doi":"10.1089/omi.1.1999.4.173","DOIUrl":null,"url":null,"abstract":"<p><p>The proton-translocating nicotinamide nucleotide transhydrogenases (TH) provide a simple model for understanding chemically coupled transmembrane proton translocation. To further our understanding of TH structure-function relationships, we have identified all sequenced homologous of these vectorial enzymes and have conducted sequence comparison studies. The NAD-binding domains of TH are homologous to bacterial alanine dehydrogenases (ADH) and eukaryotic saccharopine dehydrogenases (SDH) as well as N5(carboxyethyl)-L-ornithine synthase of Lactococcus lactis and dipicolinate synthase of Bacillus subtilis. A multiple alignment, a phylogenetic tree, and two signature sequences for this family, designated the TH-ADH-SDH or TAS superfamily, have been derived. Additionally, the TH family has been characterized. Phylogenetic analyses suggested that these proteins have evolved without inter-system shuffling. However, interdomain splicing-fusion events have occurred during the evolution of several of these systems. Analyses of the multiple alignment for the TH family revealed that domain conservation occurs in the order: NADP-binding domain (domain III) > NAD-binding domain (domain I) > proton-translocating transmembrane domain (domain II). A topologic model for the proton-translocating transmembrane domain consistent with published data is presented, and a possible involvement of specific transmembrane alpha-helical segments in channel formation is suggested.</p>","PeriodicalId":79689,"journal":{"name":"Microbial & comparative genomics","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/omi.1.1999.4.173","citationCount":"6","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Microbial & comparative genomics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1089/omi.1.1999.4.173","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 6
Abstract
The proton-translocating nicotinamide nucleotide transhydrogenases (TH) provide a simple model for understanding chemically coupled transmembrane proton translocation. To further our understanding of TH structure-function relationships, we have identified all sequenced homologous of these vectorial enzymes and have conducted sequence comparison studies. The NAD-binding domains of TH are homologous to bacterial alanine dehydrogenases (ADH) and eukaryotic saccharopine dehydrogenases (SDH) as well as N5(carboxyethyl)-L-ornithine synthase of Lactococcus lactis and dipicolinate synthase of Bacillus subtilis. A multiple alignment, a phylogenetic tree, and two signature sequences for this family, designated the TH-ADH-SDH or TAS superfamily, have been derived. Additionally, the TH family has been characterized. Phylogenetic analyses suggested that these proteins have evolved without inter-system shuffling. However, interdomain splicing-fusion events have occurred during the evolution of several of these systems. Analyses of the multiple alignment for the TH family revealed that domain conservation occurs in the order: NADP-binding domain (domain III) > NAD-binding domain (domain I) > proton-translocating transmembrane domain (domain II). A topologic model for the proton-translocating transmembrane domain consistent with published data is presented, and a possible involvement of specific transmembrane alpha-helical segments in channel formation is suggested.