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A proposed position of a disulfide bridge in the molecules of cinnamomin and porrectin ‐ two new type II ribosome‐inactivating proteins isolated from the seeds of camphor trees
Author(s) -
Liu WangYi,
Chen HuaiYang,
Chen WenFeng,
Li XiangDong,
Ulbrich Norbert,
Schröder Werner
Publication year - 1998
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549800202102
Subject(s) - ricin , ribosome inactivating protein , cysteine , homology (biology) , biochemistry , chemistry , ribosome , amino acid , gene isoform , peptide sequence , biology , stereochemistry , rna , gene , toxin , enzyme
The N‐terminal amino acid sequences of A‐ and B‐chains of three isoforms of cinnamomin and porrectin ‐ two new type II ribosome‐inactivating proteins purified from the seeds of camphor trees have been compared with themselves and with that of ricin and abrin. It has completely homologous sequence of A‐chain of six isoforms, and the same of six B‐chain sequences. However, among 10 amino acids of the N‐terminal sequence of the A‐chain there is only 20% homology between cinnamomin/porrectin and abrin, no homology between cinnamomin/porrectin and ricin. In their B‐chain, there are 60% homology between cinnamomin/porrectin and ricin, the fourth position is always occupied by cysteine. Compared with that of ricin/abrin, we proposed that the position of a disulfide bridge is at fourth cysteine in the B‐chain of cinnamomin/porrectin and a cysteine nearby the C‐terminus of A‐chain of cinnamomin/porrectin.