In vitro synthesis of chloroplast ferredoxin as a high molecular weight precursor in a cell-free protein synthesizing system from wheat germs

Abstract

RNA isolated from leaves of Nicotiana tabacum, etiolated leaves of Phaseolus vulgaris and from cells of Chlamydomonas reinhardii, can be translated in cell-free extracts derived from wheat germs. The in vitro products were identified by SDS electrophoresis after immunoprecipitation with specific antisera against ferredoxin. The in vitro products appeared to have a Mr 20,500, in contrast to authentic ferredoxin that has a Mr 17,000. We propose that chloroplast ferredoxin is synthesized in vitro as a biosynthetic precursor. Ferredoxin synthesis was found to be associated with poly(A)-RNA, which supports our previous conclusion that ferredoxin messenger is a transcript from the DNA of the nucleus. © 1978.