Search PubMed⌕ Search

Biomedical subjects

A B Legocki

Publications and source records attributed to A B Legocki.

At least 55 records · Page 3Linked to original sources
PubMed1978

5'-Terminal 7-methylguanosine and mRNA function. The effect of enzymatic decapping and of cap analogs on translation of tobacco-mosaic-virus RNA and globin mRNA in vitro.

1. Decapped tobacco mosaic virus (TMV) RNA and rabbit globin mRNA were prepared by enzymic treatment of RNAs with nucleotide pyrophosphatase purified from potato. The extent of removal of 5'-terminal 7-methylguanosine 5'-monophosphate (m7GMP) from TMV RNA was at least 97% as estimated by labeling of the 5' termini in vitro with S-adenosyl[methyl-3H]methionine catalysed by vaccinia virus methyltransferases. 2. The effect of enzymic decapping was compared with the effect of cap analogs on mRNAs translation in a nuclease-treated rabbit reticulocyte lysate and in a wheat germ extract. When translation was studied at low K+ concentration, little or no dependence on 5'-terminal 7-methylguanosine was found with either cell-free system. The importance of the 5'-terminal cap for the efficient translation of TMV RNA and globin mRNA increased as the concentration of K+ in a protein-synthesis system was raised. In a reticulocyte lysate analogs and enzymic decapping had a similar effect on translation. In a wheat germ extract, mRNA decapping resulted in a more pronounced decrease of mRNA activity, presumably due to the increased susceptibility of decapped mRNAs to the nucleases present in this protein synthesis system. 3. The requirement for a 5'-terminal cap was similar for the synthesis of 130,000-Mr and 165,000-Mr polypeptides coded by TMV RNA. This indicates that both proteins may be initiated at the common site close to the 5' terminus.

Animals↗
PubMed1978

Isolationand in vitro translation of leghaemoglobin mRNA from yellow lupin root nodules.

Messenger RNA for leghaemoglobin, extracted from polysomes of yellow lupin root nodules, was purified by chromatography on oligo(dT1-cellulose followed by sucrose-gradient centrifugation. Leghaemoglobin mRNA activity was assayed in a cell-free protein synthesizing system derived from wheat germ. The purified mRNA was sedimented in surcrose gradient in the 9S region which corresponds to a molecular weight of about 225,000. The poly(A) segment was estimated to be 66 nucleotides in length, based on hybridization with [3H]poly(U). Analysis of the translation product using immunoprecipitation and polyacrylamide-gel electrophoresis in denaturing conditions revealed that the product made in vitro was identical with authentic leghaemoglobin.

Cell-Free System↗
PubMed1977

Peptidyl transferase activity in wheat germ ribosomes. Effect of some antibiotics.

The formation of N-acetyl-leucyl-puromycin in a "fragment reaction" catalyzed by 80 S ribosomes from wheat germ was characterized. The reaction product was identified by high-voltage electrophoresis. The fragment reaction is inhibited by sparsomycin, blasticidin S, gougerotin and to a lesser degree by amicetin and tetracycline. Formation of an acLeu-pentanucleotide-ribosomes complex was strongly stimulated by sparsomycin.

Acyltransferases↗
PubMed1974

Role of phospholipids in the multiple forms of mammalian elongation factor 1.

Evidence is presented that high-molecular-weight aggregates of elongation factor 1 from calf brain and liver contain phospholipids. Sucrose gradient analysis has shown that these high-molecular-weight species can be converted to a low-molecular-weight form after incubation with different phospholipase preparations. In addition, a partially purified elongation factor 1 from rabbit reticulocytes is also converted to a low-molecular-weight species by phospholipase treatment. These data indicate that phospholipids are involved in maintaining the integrity of the high-molecular-weight species and support the view that this species is an aggregate of the low-molecular-weight elongation factor 1.

Animals↗