title: Misincorporation of the proline homologue Aze (azetidine-2-carboxylic acid) into recombinant myelin basic protein.
abstract: We have evaluated the effects of the proline homologue Aze (1) (azetidine-2-carboxylic acid) on growth of Escherichia coli strains used to over-express recombinant forms of murine myelin basic protein (rmMBP), and on the degree of misincorporation. Addition of Aze to minimal media resulted in severe diminution of growth rate, but rmMBP could still be produced and purified. Mass spectrometry indicated that a detectable proportion of the rmMBP produced had incorporated Aze instead of proline (Pro), to a maximum of three of eleven possible sites. Molecular modelling of a proline-rich region of rmMBP illustrated that the misincorporation of Aze at any site would cause a severe bend in the polypeptide chain, and that multiple Pro-->Aze substitutions would completely disrupt a poly-proline type II structure that has been conjectured to be functionally significant.
authors.affiliation: Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Kyrylo
authors.initials: K
authors.lastname: Bessonov
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Bamm
authors.forename: George
authors.initials: G
authors.lastname: Harauz
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001383:Azetidinecarboxylic Acid / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D051379:Mice; D015394:Molecular Structure; D004676:Myelin Basic Protein / Q000737:chemistry / Q000378:metabolism*; D011108:Polymers; D011392:Proline / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D004676:Myelin Basic Protein; D011108:Polymers; D011994:Recombinant Proteins; D001383:Azetidinecarboxylic Acid; D011392:Proline