Occurrence of beta-hydroxylated asparagine residues in non-vitamin K-dependent proteins containing epidermal growth factor-like domains.
Vitamin K-dependent bovine protein S has been shown to contain a posttranslationally hydroxylated asparagine within a conserved sequence in three of its epidermal growth factor (EGF)-like domains. In a review of amino acid sequences deduced from cDNA data, we have observed that a conserved sequence containing a potential asparagine hydroxylation site exists within EGF-like domains of a variety of functionally diverse proteins. We have studied a number of these and report the presence of erythro-beta-hydroxyasparagine (e-beta Hyn) in three non-vitamin K-dependent proteins: the plasma complement proteins C1r and C1s (where overbar indicates activated form) and the urinary protein uromodulin. For each protein, e-beta Hyn was identified in enzyme digests following the initial observation of erythro-beta-hydroxyaspartic acid (e-beta Hya) in acid hydrolysates of the proteins. e beta Hya and e-beta Hyn residues are detected by a postcolumn derivatization cation-exchange HPLC method herein described. HPLC isolation of the presumptive e-beta Hyn residue from enzyme digests of intact C1r allowed confirmation of its structure by GC/MS. Based upon available cDNA sequence data and observation of e-beta Hya in acid hydrolysates, we suggest other proteins in which e-beta Hyn may occur.
Przysiecki
C T
CT
Department of Pharmacology, Merck Sharp & Dohme Research Laboratories, West Point, PA 19486.
Staggers
J E
JE
Ramjit
H G
HG
Musson
D G
DG
Stern
A M
AM
Bennett
C D
CD
Friedman
P A
PA
D001216:Asparagine / Q000031:analogs & derivatives* / Q000032:analysis; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D003166:Complement Activating Enzymes / Q000032:analysis*; D003172:Complement C1 / Q000032:analysis*; D015923:Complement C1r; D003173:Complement C1s / Q000032:analysis*; D004815:Epidermal Growth Factor; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D009088:Mucoproteins / Q000032:analysis*; D011499:Protein Processing, Post-Translational; D012689:Sequence Homology, Nucleic Acid; D058949:Uromodulin
D003172:Complement C1; D009088:Mucoproteins; C548612:UMOD protein, human; D058949:Uromodulin; C050931:3-hydroxyasparagine; C011274:3-hydroxyaspartic acid; D001224:Aspartic Acid; D004815:Epidermal Growth Factor; D001216:Asparagine; D003166:Complement Activating Enzymes; D015923:Complement C1r; D003173:Complement C1s