Sequence analysis of ripening-related cytochrome P-450 cDNAs from avocado fruit.
The ripening of avocado fruit is associated with the expression of a number of mRNAs concomitant with overt changes in texture and flavor. Two overlapping cDNAs for a mRNA that accumulates during ripening were identified. Sequence analysis of these two cDNAs revealed a polypeptide of 471 amino acids with characteristics of a typical P-450: an N-terminal hydrophobic membrane anchor, a conserved heme-binding domain in the C-terminal region, and patches of similarity to various P-450 family members. Further evidence that this polypeptide represents a cytochrome P-450 oxidase comes from the recent isolation and characterization of a cytochrome P-450 from ripe avocado mesocarp [O'Keefe, D. P. & Leto, K. J. (1989) Plant Physiol. 89, 1141-1149]. The N terminus of the predicted polypeptide in the cDNAs is identical to the N terminus of the purified avocado P-450. Gel blot analysis of RNA from fruit at various stages of ripening showed the accumulation of an 1800-nucleotide P-450 mRNA that hybridized to the P-450 cDNA. The P-450 protein predicted by the avocado cDNA sequence shares less than 40% positional identity with any known P-450 gene family. We propose therefore that it be placed in a separate family, P450LXXI, and that the corresponding gene from avocado be named cyp71A1.
Department of Biological Sciences, University of California, Santa Barbara 93106.
K R
KR
Bozak
H
H
Yu
R
R
Sirevåg
R E
RE
Christoffersen
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D005638:Fruit; D015723:Gene Library; D008969:Molecular Sequence Data; D005810:Multigene Family; D015345:Oligonucleotide Probes; D010944:Plants / Q000235:genetics*; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D012313:RNA; D004247:DNA; D003577:Cytochrome P-450 Enzyme System