Primary structure of elongation factor 1β from Artemia

Abstract

cDNA complementary to mRNA coding for the elongation factor EF‐1β has been cloned. A γgt 11 cDNA library has been screened with an antiserum against EF‐1β which exchanges GDP bound to EF‐1α with exogenous GTP during protein synthesis. The derived amino acid sequence corresponds to 208 amino acids including the N‐terminal methionine which is absent in the mature protein. About sixty percent of the protein was sequenced by direct protein sequence analysis. Comparison of Artemis salina EF‐1β with Escherichia coli EF‐Ts shows no evident homology.

Comparison of phosphorylation of elongation factor 1 from different species by caScin kinase II

“…With reticulocyte EF-1, which can be phosphorylated by casein kinase II only in the presence of polylysine, approximately equal amounts of phosphoserine and phosphothreonine were observed. kinase II confirms the results obtained by Janssen and Mfller [10] using EF-I~3, containing traces of a casein kinase II-like enzyme. This subunit is modified on serine 89 [10], in a sequence which agrees with the consensus sequence for casein kinase II [11].…”

“…kinase II confirms the results obtained by Janssen and Mfller [10] using EF-I~3, containing traces of a casein kinase II-like enzyme. This subunit is modified on serine 89 [10], in a sequence which agrees with the consensus sequence for casein kinase II [11]. Casein kinase II also modifies a single subunit in wheat germ (Mr 36 000).…”

“…The observation that a single subunit from each species is modified by casein kinase II leads us to suggest that the Mr 26 000 subunit of Artemia EF-1 (denoted as/5 in reference [10]) is equivalent to the Mr 33 000 subunit from reticulocytes (denoted as t5 in reference [7]) and the wheat germ polypeptide Mr 36 000 [9]. This subunit would correspond to the low Mr subunit of EF-1 (Table II) which, along with the higher Mr subunit, catalyzes the exchange of GDP bound to EF-lo~ for GTP.…”

“…In Artemia salina, one of the subunits, Mr 26 000, has been shown to be phosphorylated at serine 89 [10]; adjacent acidic residues at the carboxyl terminus provide a recognition sequence for casein kinase II [11]. The same subunit is phosphorylated in vitro by a casein kinase II-like protein kinase copurifying with the elongation factor [10].…”

“…The same subunit is phosphorylated in vitro by a casein kinase II-like protein kinase copurifying with the elongation factor [10]. Recent reports indicate EF-1 is phosphorylated on a Mr 47 000 subunit in maturing Xenopus oocytes during meiotic cell division and is modified in vitro by the CDC2 protein kinase [12,13].…”