Cloning and nucleotide sequence of the gene braB coding for the sodium-coupled branched-chain amino acid carrier in Pseudomonas aeruginosa PAO
✍ Scribed by Hoshino, Toshimitsu ;Kose, Kumiko ;Uratani, Yoshihiko
- Publisher
- Springer
- Year
- 1990
- Tongue
- English
- Weight
- 728 KB
- Volume
- 220
- Category
- Article
- ISSN
- 0026-8925
No coin nor oath required. For personal study only.
✦ Synopsis
The gene braB, encoding the Na+-coupled carrier for branched-chain amino acids in Pseudomonas aerugin- osa PAO, was cloned on cosmid pMMB34. The cosmid clones carrying the braB gene were identified as those that restored growth at low leucine concentration and Na+-dependent leucine transport activity to P. aeruginosa PAO3536 defective in the transport of branched-chain amino acids. Determination of the nucleotide sequence of the DNA fragment shows that the braB gene comprises 1311 bp and encodes a hydrophobic protein of 437 amino acids with a calculated Mr of 45 279. The hydropathy profile suggests that there exist in the carrier protein 12 hydrophobic segments long enough to traverse the membrane. The amino acid sequence shows a high degree of homology with the brnQ product, a branched-chain amino acid carrier of Salmonella typhimurium, while no homology in the nucleotide sequences is found in the braB and brnQ genes.