Characteristic analysis of the ampC gene encoding beta-lactamase from Photobacterium phosphoreum.
The ampC gene of Photobacterium phosphoreum ATCC 11040 was cloned and identified. Nucleotide sequence of the regulatory region R&R and the ampC gene (GenBank Accession No. AY787792) from P. phosphoreum has been determined, and the encoded beta-lactamase is deduced. The beta-lactamase encoded by the ampC gene has a calculated M(r) 31,198 and comprises 285 amino acid residues (pI 7.35). There is a signal peptide of 20 amino acid residues MKLRFIASTLLLSFSQLASA to lead the beta-lactamase secretion, and the cleavage site is between ASA-Q; thus, the matured protein only has M(r) 29,019 and comprises 265 amino acid residues (pI 6.21). The specific amino acid residues STFK (65th to 68th), SDN (125th to 127th), and D (158th) located 33 residues downstream from the SDN loop of the class A beta-lactamases are highly conserved, but the KTG is not found. The gene order of the ampC is <--ufo-R&R-ampC-->, the genes running in the opposite directions. Functional analysis elicits that R&R([ampC]) does function to lead to the gene expression. Primer extension assay elicits that the ampC gene's transcriptional initiation +1 is -26 C upstream of the start codon; the P([I])-promoter should be the promoter response for the gene expression. Analysis of the R&R([ampC]) elicits that the upstream activator binding sequence Sigma UAS TGTTTAAATACGCTTTGAACA is like the two-component regulator binding sequence TGT-N(8-12)-ACA. It implies that P. phosphoreum ampC gene could be under-regulated by the specific two-component regulator.
Lin
Juey-Wen
JW
Institute of Biochemistry, National Chung Hsing University, Taichung 40227, Taiwan, ROC. jwlin@nchu.edu.tw
Weng
Shu-Fen
SF
Chao
Yuh-Fen
YF
Chung
Yi-Ting
YT
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D001483:Base Sequence; D003001:Cloning, Molecular; D024881:Drug Resistance, Bacterial / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D010776:Photobacterium / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D013997:Time Factors; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C048795:AmpC beta-lactamases; D001618:beta-Lactamases