Open AccessThe amino acid sequence of snapping turtle ( Chelydra serpentina ) ribonuclease
Author(s) -
BEINTEMA Jaap J.,
BROOS Jaap,
MEULENBERG Janneke,
SCHÜLLER Cornelis
Publication year - 1985
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1985.tb09301.x
Subject(s) - chelydra , ribonuclease , s tag , residue (chemistry) , pancreatic ribonuclease , biochemistry , amino acid , peptide sequence , biology , bovine pancreatic ribonuclease , chemistry , turtle (robot) , rna , gene , fishery
Snapping turtle ( Chelydra serpentina ) ribonuclease was isolated from pancreatic tissue. Turtle ribonuclease binds much more weakly to the affinity chromatography matrix used than mammalian ribonucleases. The amino acid sequence was determined from overlapping peptides obtained from three different digests. The N‐terminal amino acid sequence of the protein determined by others [E. A. Barnard, M. S. Cohen, M. H. Gold J.‐K. Kim (1972) Nature ( Lond. ) 240 , 395‐398] and homology were used as additional evidence for several overlaps. The polypeptide chain consists of 119 amino acid residues. Compared to most ribonucleases the N‐terminal residue, three residues in the loop near residue 71 and two residues in the loop near residue 114 are deleted, and there is one additional residue in the loop near residue 23. The half‐cystines at positions 65 and 72, which form a disulfide bond in mammalian ribonucleases, are not present in turtle ribonuclease. Turtle ribonuclease differs from bovine ribonuclease at 70 of the 118 positions where both proteins have amino acid residues. Turtle ribonuclease contains no carbohydrate, although the enzyme possesses a recognition site for carbohydrate attachment in the sequence Asn‐Ala‐Ser (positions 76‐78).