We located the polypeptide nascent chain as it leaves cytoplasmic ribosomes from the plant Lemna gibba by immune electron microscopy using antibodies against the small subunit of the enzyme ribulose-1,5-bisphosphate carboxylase. Similar studies with Escherichia coli ribosomes, using antibodies directed against the enzyme beta-galactosidase, show that the polypeptide nascent chain emerges in the...

Acetylation is the most frequently occurring chemical modification of the alpha-NH2 group of eucaryotic proteins and is catalyzed by N alpha-acetyltransferase. The yeast enzyme is encoded by the AAA1 (amino-terminal alpha-amino acetyltransferase) gene. A null mutation (aaa1-1) created by gene replacement, while not lethal, slows cell growth and results in heterogeneous colony morphology. In com...

Initiation of eukaryotic DNA replication is a tightly controlled process. Replication initiates at multiple specific sites (replication origins) that have been licensed for replication, following the cell cycle-dependent, multi-step assembly of specific factors. Thus, replication origins occur in two chromatin states: a replication-competent pre-replicative (pre-RC) state, when a number of repl...

An isolation technique for Chlamydia trachomatis using McCoy cells is described. In contrast to earlier techniques employing such cells, no pretreatment of the cells was used. The glutarimide antibiotic cycloheximide was added to the culture medium used for incubating the cells after infection. Cycloheximide was used at concentrations that depressed, but did not completely inhibit, the metaboli...