Proc. Natl. Acad. Sci. USA, 74 (3). pp. 1082-1085.
Translation of polyadenylated mRNA of Chlamydomonas reinhardtii in a cell-free wheat germ system resulted in the synthesis of numerous discrete polypeptides. Among them was a species with molecular weight 20,000 that was immunoprecipitated specifically by antibodies raised against the authentic small subunit (16,500 daltons) of ribulose-1,5-bisphosphate carboxylase [3-phospho-D-glycerate carboxy-lyase(dimerizing), EC 126.96.36.199]. Since the immunoprecipitated polypeptide has a larger molecular weight by approximately 3500 than the small subunit (S) it was identified as a putative biosynthetic precursor (pS). Post-translational conversion of pS by a specific endoprotease yielded two detectable products: one apparently identical in size to S and the other, a small peptide, presumably representing the remainder of pS. The endoprotease requires sulfhydryl groups for its activity and is present in a C. reinhardtii postribosomal supernatant as well as in a free polysome fraction. The latter could account for the observation that completion of nascent chains in free polysomes yielded S but not pS. We propose that pS is an extacloroplastic form of S and that the smallfpeptide portion plays a role in the transfer of S into the chloroplast.
|Journal or Publication Title:||Proc. Natl. Acad. Sci. USA|
|Page Range:||pp. 1082-1085|
|Faculties / Institutes:||Service facilities > Center for Molecular Biology Heidelberg|
|Subjects:||570 Life sciences|
|Schriftenreihe ID:||Works by Bernhard Dobberstein|