Saccharide transporter

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Phosphotransferase system, EIIC
Crystal structure of a phosphorylation-coupled saccharide transporter. PDB 3qnq.[1]
Pfam PF02378
Pfam clan CL0493
InterPro IPR003352
TCDB 4.A.3
OPM superfamily 255
OPM protein 3qnq

The bacterial phosphoenolpyruvate: sugar phosphotransferase system (PTS) is a multi-protein system involved in the regulation of a variety of metabolic and transcriptional processes. The PTS catalyzes the phosphorylation of incoming sugar substrates concomitant with their translocation across the cell membrane. The general mechanism of the PTS is the following: a phosphoryl group from phosphoenolpyruvate (PEP) is transferred to enzyme-I (EI) of PTS which in turn transfers it to a phosphoryl carrier protein (HPr). Phospho-HPr then transfers the phosphoryl group to a sugar-specific permease which consists of at least three structurally distinct domains (IIA, IIB, and IIC) [2] which can either be fused together in a single polypeptide chain or exist as two or three interactive chains, formerly called enzymes II (EII) and III (EIII). The IIC domain catalyzes the transfer of a phosphoryl group from IIB to the sugar substrate.


  1. ^ Cao, Y.; Jin, X.; Levin, E. J.; Huang, H.; Zong, Y.; Quick, M.; Weng, J.; Pan, Y.; Love, J.; Punta, M.; Rost, B.; Hendrickson, W. A.; Javitch, J. A.; Rajashankar, K. R.; Zhou, M. (2011). "Crystal structure of a phosphorylation-coupled saccharide transporter". Nature. 473 (7345): 50–54. doi:10.1038/nature09939. PMC 3201810Freely accessible. PMID 21471968. 
  2. ^ Saier MH, Reizer J (March 1992). "Proposed uniform nomenclature for the proteins and protein domains of the bacterial phosphoenolpyruvate: sugar phosphotransferase system". J. Bacteriol. 174 (5): 1433–8. PMC 206537Freely accessible. PMID 1537788. 

This article incorporates text from the public domain Pfam and InterPro IPR003352