Protein Family Models

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 lactose/cellobiose-specific family are one of four structurally and functionally distinct group IIA PTS system enzymes. This family of proteins normally function as a homotrimer, stabilised by a centrally located metal ion [1]. Separation into subunits is thought to occur after phosphorylation. [1]. 9261069. The structure of enzyme IIAlactose from Lactococcus lactis reveals a new fold and points to possible interactions of a multicomponent system. Sliz P, Engelmann R, Hengstenberg W, Pai EF;. Structure 1997;5:775-788. (from Pfam)

Date:

2024-10-16

The PTS Lactose-N,N?-Diacetylchitobiose-b-glucoside (Lac) Family (TC 4.A.3) Bacterial PTS transporters transport and concomitantly phosphorylate their sugar substrates, and typically consist of multiple subunits or protein domains. The Lac family includes several sequenced lactose (b-galactoside) permeases of Gram-positive bacteria as well as the E. coli N,N?-diacetylchitobiose (Chb) permease which can transport aromatic b-glucosides and cellobiose as well as the chitin disaccharide, Chb, but only Chb induces expression of the chb operon. While the Lac permeases consist of two polypeptide chains (IIA and IICB), the Chb permease of E. coli consists of three (IIA, IIB and IIC). In B. subtilis, a PTS permease similar to the Chb permease of E. coli is believed to transport lichenan (a b-1,3;1,4 glucan) degradation products, oligosaccharides of 2-4 glucose units. This Hmm is specific for the IIA subunit of the Lac PTS family.

Gene:

lacF

Date:

2022-03-28