TY - JOUR

T1 - Primary structure, cell-free synthesis and mitochondrial targeting of the 8.2 kDa protein of cytochrome c reductase from potato

AU - Braun, Hans-Peter

AU - Kruft, Volker

AU - Schmitz, Udo

N1 - Funding information: We wish to thank H. Mentzel for excellent technical assistance. This work was supported by the Deutsche Forschungsgemeinschaft, grant Schm. 698/2, and by the BMFT.

PY - 1994/12/30

Y1 - 1994/12/30

N2 - Cytochrome c reductase from potato comprises ten subunits with apparent molecular sizes between 55 and < 10 kDa. The subunit with the highest electrophoretic mobility on SDS-polyacrylamide gels was isolated and analysed by cyclic Edman degradation. Mixtures of degenerative oligonuleotides were derived from the obtained sequence data and used for the isolation of corresponding cDNA clones. The clones encode a protein of 72 amino acids which exhibits significant sequence identity with a 9.5 kDa subunit of cytochrome c reductase from bovine and a 11 kDa subunit of the enzyme complex from yeast. Comparison between the deduced amino acid sequence of the open reading frame and the sequence of the mature protein reveals that only the initiator methionine is absent in the functional subunit. Hence the protein has a calculated molecular mass of 8.2 kDa. Transcripts of the potato 8.2 kDa protein were not translated in reticulocyte lysates but in vitro translation worked efficiently with wheat germ lysate. Import of the radiolabelled protein into isolated mitochondria from potato seems to depend on a potential across the inner membrane and confirms the absence of a cleavable mitochondrial presequence.

AB - Cytochrome c reductase from potato comprises ten subunits with apparent molecular sizes between 55 and < 10 kDa. The subunit with the highest electrophoretic mobility on SDS-polyacrylamide gels was isolated and analysed by cyclic Edman degradation. Mixtures of degenerative oligonuleotides were derived from the obtained sequence data and used for the isolation of corresponding cDNA clones. The clones encode a protein of 72 amino acids which exhibits significant sequence identity with a 9.5 kDa subunit of cytochrome c reductase from bovine and a 11 kDa subunit of the enzyme complex from yeast. Comparison between the deduced amino acid sequence of the open reading frame and the sequence of the mature protein reveals that only the initiator methionine is absent in the functional subunit. Hence the protein has a calculated molecular mass of 8.2 kDa. Transcripts of the potato 8.2 kDa protein were not translated in reticulocyte lysates but in vitro translation worked efficiently with wheat germ lysate. Import of the radiolabelled protein into isolated mitochondria from potato seems to depend on a potential across the inner membrane and confirms the absence of a cleavable mitochondrial presequence.

KW - (S. tuberosum)

KW - Cytochrome bc complex

KW - Cytochrome c reductase

KW - Mitochondrion

KW - Protein transport

KW - Respiratory chain

UR - http://www.scopus.com/inward/record.url?scp=0028598297&partnerID=8YFLogxK

U2 - 10.1016/0005-2728(94)90057-4

DO - 10.1016/0005-2728(94)90057-4

M3 - Article

C2 - 7803451

AN - SCOPUS:0028598297

VL - 1188

SP - 367

EP - 372

JO - BBA - Bioenergetics

JF - BBA - Bioenergetics

SN - 0005-2728

IS - 3

ER -