title: Expression and processing of cyanobacterial Mn-stabilizing protein in Escherichia coli.
abstract: The woxA gene of cyanobacterium Anacystis nidulans R2, which encodes the precursor of the Mn-stabilizing protein involved in photosynthetic water oxidation, was found to be expressed in Escherichia coli. The 30-kDa expression product was indistinguishable from the authentic mature protein on SDS/PAGE. Upon fractionation of E. coli cells, the expression product was co-precipitated with the membrane fraction, which is consistent with the water-insoluble nature of the authentic mature protein. Analysis of the amino-terminal amino acid sequence of the product revealed that it is identical to the sequence from the 28th residue of the precursor, indicating that the precursor is processed in E. coli. The expression product was digested by trypsinization of E. coli spheroplasts, but not by that of intact cells. This observation suggests that the product is secreted from the cytoplasmic membrane, but not from the outer membrane. The occurrence of both processing and secretion suggests that a signal peptidase of E. coli can recognize the structure for translocation across the thylakoid membrane. Comparison of the signal sequence and the presequence of sweet potato sporamin A suggests that the processing enzymes of the thylakoid membrane and endoplasmic reticulum possess a common substrate specificity.
authors.affiliation: Department of Chemistry, Faculty of Science, Toho University, Funabashi, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kuwabara
authors.forename: R
authors.initials: R
authors.lastname: Nagata
authors.forename: K
authors.initials: K
authors.lastname: Shinohara
mesh_terms: D000595:Amino Acid Sequence; D004926:Escherichia coli / Q000235:genetics*; D015870:Gene Expression; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D045332:Photosystem II Protein Complex; D010940:Plant Proteins / Q000235:genetics*; D014176:Protein Biosynthesis; D011506:Proteins; D014169:Transformation, Bacterial
chemical_list: D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D011506:Proteins; C054266:photosystem II manganese-stabilizing protein