Carbohydrate transporters of the bacterial phosphoenolpyruvate: sugar phosphotransferase system (PTS)
2001; Wiley; Volume: 504; Issue: 3 Linguagem: Inglês
10.1016/s0014-5793(01)02705-3
ISSN1873-3468
AutoresChristian Siebold, Karin Flükiger, Rudolf Beutler, Bernhard Erni,
Tópico(s)Enzyme Structure and Function
ResumoThe glucose transporter of Escherichia coli couples translocation with phosphorylation of glucose. The IICB Glc subunit spans the membrane eight times. Split, circularly permuted and cyclized forms of IICB Glc are described. The split variant was 30 times more active when the two proteins were encoded by a dicistronic mRNA than by two genes. The stability and activity of circularly permuted forms was improved when they were expressed as fusion proteins with alkaline phosphatase. Cyclized IICB Glc and IIA Glc were produced in vivo by RecA intein‐mediated trans ‐splicing. Purified, cyclized IIA Glc and IICB Glc had 100% and 30% of wild‐type glucose phosphotransferase activity, respectively. Cyclized IIA Glc displayed increased stability against temperature and GuHCl‐induced unfolding.
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