Title: Phosphoglycerate kinase and triosephosphate isomerase from the hyperthermophilic bacterium Thermotoga maritima form a covalent bifunctional enzyme complex.
Abstract: Research Article1 February 1995free access Phosphoglycerate kinase and triosephosphate isomerase from the hyperthermophilic bacterium Thermotoga maritima form a covalent bifunctional enzyme complex. H. Schurig H. Schurig Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany. Search for more papers by this author N. Beaucamp N. Beaucamp Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany. Search for more papers by this author R. Ostendorp R. Ostendorp Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany. Search for more papers by this author R. Jaenicke R. Jaenicke Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany. Search for more papers by this author E. Adler E. Adler Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany. Search for more papers by this author J.R. Knowles J.R. Knowles Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany. Search for more papers by this author H. Schurig H. Schurig Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany. Search for more papers by this author N. Beaucamp N. Beaucamp Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany. Search for more papers by this author R. Ostendorp R. Ostendorp Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany. Search for more papers by this author R. Jaenicke R. Jaenicke Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany. Search for more papers by this author E. Adler E. Adler Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany. Search for more papers by this author J.R. Knowles J.R. Knowles Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany. Search for more papers by this author Author Information H. Schurig1, N. Beaucamp1, R. Ostendorp1, R. Jaenicke1, E. Adler1 and J.R. Knowles1 1Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany. The EMBO Journal (1995)14:442-451https://doi.org/10.1002/j.1460-2075.1995.tb07020.x PDFDownload PDF of article text and main figures. ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InMendeleyWechatReddit Figures & Info Phosphoglycerate kinase (PGK) from the hyperthermophilic bacterium Thermotoga maritima has been purified to homogeneity. A second larger enzyme with PGK activity and identical N-terminal sequence was also found. Surprisingly, this enzyme displayed triosephosphate isomerase (TIM) activity. No other TIM is detectable in T. maritima crude extracts. As shown by ultracentrifugal analysis, PGK is a 43 kDa monomer, whereas the bifunctional PGK-TIM fusion protein is a homotetramer of 240-285 kDa. SDS-PAGE indicated a subunit size of 70 kDa for the fusion protein. Both enzymes show high thermostability. Measurements of the catalytic properties revealed no extraordinary results. pH optima, Km values and activation energies were found to be in the range observed for other PGKs and TIMs investigated so far. The corresponding pgk and tpi genes are part of the apparent gap operon of T. maritima. This gene segment contains two overlapping reading frames, where the 43 kDa PGK is encoded by the upstream open reading frame, the pgk gene. On the other hand, the 70 kDa PGK-TIM fusion protein is encoded jointly by the pgk gene and the overlapping downstream open reading frame of the tpi gene. A programmed frameshift may be responsible for this fusion. A comparison of the amino acid sequence of both the PGK and the TIM parts of the fusion protein with those of known PGKs and TIMs reveals high similarity to the corresponding enzymes from different procaryotic and eucaryotic organisms. Previous ArticleNext Article Volume 14Issue 31 February 1995In this issue RelatedDetailsLoading ...