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Identification of two structurally related proteins involved in proteolytic processing of precursors targeted to the chloroplast.
Author(s) -
Oblong J.E.,
Lamppa G.K.
Publication year - 1992
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1992.tb05540.x
Subject(s) - biology , chloroplast , identification (biology) , biochemistry , proteolysis , computational biology , microbiology and biotechnology , botany , enzyme , gene
Two proteins of 145 and 143 kDa were identified in pea which co‐purify with a chloroplast processing activity that cleaves the precursor for the major light‐harvesting chlorophyll binding protein (preLHCP). Antiserum generated against the 145/143 kDa doublet recognizes only these two polypeptides in a chloroplast soluble extract. In immunodepletion experiments the antiserum removed the doublet, and there was a concomitant loss of cleavage of preLHCP as well as of precursors for the small subunit of Rubisco and the acyl carrier protein. The 145 and 143 kDa proteins co‐eluted in parallel with the peak of processing activity during all fractionation procedures, but they were not detectable as a homo‐ or heterodimeric complex. The 145 and 143 kDa proteins were used separately to affinity purify immunoglobulins; each preparation recognized both polypeptides, indicating that they are antigenically related. Wheat chloroplasts contain a soluble species similar in size to the 145/143 kDa doublet.