MOLECULAR CHARACTERIZATION OF A GENE ENCODING A MEMBRANE-PROTEIN OF SPIROPLASMA-CITRI

A 9.6-kb genomic DNA segment, previously cloned from the phytopathogen Spiroplasma citri BR3-3X [Fletcher et al. (1981) Phytopathology 71, 1 073-1080], contained several open reading frames including one encodin g a 58-kDa protein. In this work, the transcription initiation site of the P58 mRNA was mapped and part of the gene was expressed in Escheri chia coli as a fusion protein, A synthetic peptide, whose sequence is included in the fusion protein, was produced. Antibodies against both the fusion protein and the peptide reacted with a 60-kDa protein in a S. citri total protein extract. Hydrophobicity characteristics of this protein and its fractionation into the detergent phase indicated that P58, which shares limited sequence similarity with the adhesin of Myc oplasma hominis and the attachment protein of M. genitalium, is an int egral membrane protein. (C) Elsevier Science B.V.