The amino terminal sequence of ATP-phosphoribosyltransferase, the first gene product of the histidine operon.

The amino terminal sequence of ATP-phosphoribosyltransferase of $\text{Salmonella typhimurium}$ has been determined by automated Edman degradation. Since this protein is the first gene product of the histidine operon, comparison of its amino terminal sequence with the genetic code allows the deduction of a partial base sequence of its mRNA and the corresponding DNA. Five of the first nine residues of ATP-phosphoribosyltransferase align with the amino terminal sequence of histidinol dehydrogenase, the second gene product of the histidine operon.     

The separation of phage promoter from bacterial lac promoter for beta-galactosidase expression in transducing phage lambda plac5.

The replication defective transducing phage λp$\text{lac}\text{5}\text{O}\text{29}\text{P}$3 carries a portion of the $\text{E.}\text{coli}\text{lac}$ operon in the $\text{b}$2 region of the lambda phage. This $\text{lac}$ operon segment contains the $\text{lac}$ promoter, the $\text{lac}$ operator, and the β-galactosidase $\text{z}$ gene, but does not contain the $\text{lac}$ repressor $\text{i}$ gene. The $\text{z}$ gene can be expressed from both the inserted $\text{lac}$ promoter and the phage promoter. When $\text{E.}\text{coli}$ strain 594 ($\text{z}$^?, $\text{i}$⁺) or JC6256 (Δ$\text{lac}$) is infected by λp$\text{lac}\text{5}\text{O}\text{29}\text{P}$3 in the absence of additional cyclic AMP, β-galactosidase synthesis is shown to be expressed from the phage promoter. When 594 (λ⁺) or JC6256 (λ⁺) is infected by λp$\text{lac}\text{5}\text{O}\text{29}\text{P}$3 in the presence of additional cyclic AMP and IPTG, β-galactosidase synthesis is shown to be expressed from the inserted $\text{lac}$ promoter.The ability to separate the phage promoter from the inserted $\text{lac}$ promoter for β-galactosidase expression will simplify the interpretation whenever λp$\text{lac}$5 is used.     

Localization of translation initiation in the message for E. coli UDP-galactose 4-epimerase: the amino terminal sequence

The amino acid sequence of $\text{E.}$$\text{coli}$ UDP-galactose 4-epimerase has been determined through the amino-terminal 28-amino acid residues using an automated protein sequenator. Alignment of UDP-galactose operon messenger RNA and the amino acid sequence of epimerase demonstrates that the first 26 bases in the mRNA are transcribed but do not take part in translation of epimerase.     

Regulation of the Escherichiacoli tryptophan operon by readthrough of UGA termination codons

The regulation of the synthesis of $\text{trp}$ operon enzymes was studied in streptomycin-resistant $\text{Escherichia}\text{coli}$ mutants temperature-sensitive for UGA suppression by normal tRNA^Trp. Our mutants carry a $\text{trp}\text{R}{}^{\mathrm{+}}$ allele that when transferred to a different genetic background causes repression of trp operon enzyme synthesis at both low (35°C) and high (42°C) temperatures; however, in our mutants with an excess of tryptophan and at increased temperatures $\text{trp}$ enzyme synthesis is derepressed. Based on our results and the sequence data of the $\text{trp}$R gene [Singleton et al. (1980) Nucleic Acids Res., 8, 1551–1560], we offer a model for the involvement of the limited misreading of UGA codons by normal charged tRNA^Trp in the autogenous regulation of the $\text{trp}$R gene expression. The UGA readthrough process may be a regulatory amplifier of the effect of tryptophan starvation.     

Nucleotide sequence of the genes for F0 components of the proton-translocating ATPase from Escherichia coli: prediction of the primary structure of F0 subunits

The 1763 nucleotide-long-DNA sequence of part of the gene cluster for the proton-translocating ATPase from $\text{E. coli}$ was determined. The sequence covers the genes for the a and b subunits of F₀ along with the intercistronic regions. In the region preceding the gene for the a subunit, a reading frame encompassing 127 amino acids was found. The primary structure of the a and b subunits were deduced and the properties of these proteins were predicted. Analysis of codon usage in these genes was made.