An invertebrate α-ketoglutarate-dependent aspartyl/asparaginyl β-hydroxylase, which posttranslationally hydroxylates specific aspartyl or asparaginyl residues within epidermal growth factor-like modules, was identified, partially purified and characterized. Preparations derived from two insect cell lines catalyzed the hydroxylation of the expected asparaginyl residue within a synthetic epidermal growth factor-like module. This activity was found to be similar to that of the purified mammalian aspartyl/asparaginyl β-hydroxylase with respect to cofactor requirements, stereochemistry and substrate sequence specificity. Furthermore, recombinant human C1r, expressed in an insect cell-derived baculovirus expression system, was also found to be hydroxylated at the expected asparaginyl residue. Thus, these results establish the potential for invertebrate aspartyl/asparaginyl hydroxylation. Since several invertebrate proteins known to be required for proper embryonic development contain a putative consensus sequence that may be required for hydroxylation, the studies presented here provide the basis for further investigations concerned with identifying hydroxylated invertebrate proteins and determining their physiologic function. © 1992.
Monkovic, D. D., VanDusen, W. J., Petroski, C. J., Garsky, V. M., Sardana, M. K., Zavodszky, P., … Friedman, P. A. (1992). Invertebrate aspartyl/asparaginyl β-hydroxylase: Potential modification of endogenous epidermal growth factor-like modules. Biochemical and Biophysical Research Communications, 189(1), 233–241. https://doi.org/10.1016/0006-291X(92)91549-6