title: In vitro translation of elastin mRNA and processing of the translated products and the signal sequence of elastin a.
abstract: Chick embryo aorta mRNAs were translated in a gel-filtered reticulocyte lysate. The translated products showed two elastin-related proteins (a and b; relative mass approximately 70 000). The translated elastin a protein was separated essentially free of the b protein by centrifugation and sodium dodecyl sulfate (SDS) - polyacrylamide gel electrophoresis. The a protein was then electroeluted from the SDS-polyacrylamide gel and a partial sequence was determined by automated Edman degradation. The NH2-terminal presequence of the elastin a protein is (formula; see text) The assigned sequence is identical to that reported for the b protein. Translation of chick embryo aorta mRNA in the presence of dog pancreas microsomal membranes segregated the a and b proteins into membrane vesicles and cotranslationally cleaved their respective presequences. The processed a and b elastin proteins were isolated together and NH2-terminal proline positions were determined. These are (formula; see text) These proline positions 4 and 8 are identical to those for NH2-terminal sequence for tropoelastin. This suggests that the signal peptidase removes the 24-residue signal peptide and thus directly generates the tropoelastin sequence, with no NH2-terminal prosequence as the intermediate.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001011:Aorta / Q000378:metabolism*; D002642:Chick Embryo; D004549:Elastin / Q000235:genetics* / Q000302:isolation & purification; D007700:Kinetics; D046911:Macromolecular Substances; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*
chemical_list: D046911:Macromolecular Substances; D012333:RNA, Messenger; D004549:Elastin