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Hypusine-containing proteins and their modifying enzymes

Thesis/Dissertation ·
OSTI ID:6948677

The aim of this study is to purify and characterize this protein and to investigate general properties of its modifying enzymes. I developed a simple four-step procedure for purifying the hyp-18K protein. This procedure resulted in an 800-fold purification of the radio-labeled protein from NB-15 mouse neuroblastoma cells. Two hypusine-containing proteins with an apparent molecular weight of 18 kDa and 20 kDa were also identified by metabolic labeling in chick embryo fibroblasts. The hyp-18K in both NB cells and chick embryo fibroblastes exhibited two isoforms: acidic form (hyp-18K{sup a}) and basic form (hyp-18K{sup b}). I also purified both hyp-20K and hyp-18K isoforms from chick embryos to homogeneity. V8 protease peptide map analysis indicated that hyp-18K{sup b} isolated from chick embryos was identical, while hyp-18K{sup a} and hyp-20K were similar, to elF-4D. The chick embryo hyp-18K{sup b}, but not hyp-18K{sup a}, co-migrated with elF-4D. When NB cell lysates were incubated with ({sup 3}H)spermidine at pH 9.5, only hyp-18K{sup b} was labeled. Lysates, labeled at pH 9.5 and then adjusted to pH 7.2, gave both hyp-18K{sup a} and hyp-18K{sup b}. These data provided evidence that hyp-18K{sup a} is derived from hyp-18K{sup b}.

Research Organization:
Rutgers--the State Univ., New Brunswick, NJ (USA)
OSTI ID:
6948677
Country of Publication:
United States
Language:
English