The acidic, glutamine-rich Mpn474 protein of Mycoplasma pneumoniae is surface exposed and covers the complete cell.
The protein Mpn474 encoded by the mpn474 gene of the human-pathogenic Mycoplasma pneumoniae contains 1033 amino acids and has an isoelectric point of 4.79, which is caused by the large excess of glutamic acid residues (11 %). Although the protein lacks recognizable export signals we showed by immuno-electron microscopy that Mpn474 is surface exposed, covering the cell completely. By combining cross-linking and careful treatment of the bacterial cells with Triton X-100, we found that this protein is weakly bound to the cell surface, while the true transmembrane protein Mpn141 (adhesin P1) is firmly attached under the same experimental conditions. A transposon mutant in the mpn474 gene, which has no obvious phenotype, served as negative control for the immunodetection.
Hegermann
Jan
J
Abteilung für Allgemeine Mikrobiologie, Institut für Mikrobiologie und Genetik, Grisebachstr. 8, D-37077 Göttingen, Germany.
Halbedel
Sven
S
Abteilung für Allgemeine Mikrobiologie, Institut für Mikrobiologie und Genetik, Grisebachstr. 8, D-37077 Göttingen, Germany.
Dumke
Roger
R
Institut für Medizinische Mikrobiologie und Hygiene, Technische Universität, Medizinische Fakultät Carl Gustav Carus, Fetscherstr. 74, D-01307 Dresden, Germany.
Regula
Jörg
J
Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.
Gabdoulline
Razif R
RR
Molecular and Cellular Modeling Group, EML Research, Schloss-Wolfsbrunnenweg 33, D-69118 Heidelberg, Germany.
Mayer
Frank
F
Abteilung für Allgemeine Mikrobiologie, Institut für Mikrobiologie und Genetik, Grisebachstr. 8, D-37077 Göttingen, Germany.
Stülke
Jörg
J
Abteilung für Allgemeine Mikrobiologie, Institut für Mikrobiologie und Genetik, Grisebachstr. 8, D-37077 Göttingen, Germany.
Herrmann
Richard
R
Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.
D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics; D015153:Blotting, Western; D004251:DNA Transposable Elements; D017353:Gene Deletion; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis* / Q000235:genetics; D016253:Microscopy, Immunoelectron; D016254:Mutagenesis, Insertional; D009177:Mycoplasma pneumoniae / Q000737:chemistry*
D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D008565:Membrane Proteins