ECF transporter

Parent categories	1. Cellular processes 1.2. Transporters
Neighbouring categories	1.2.1. ABC transporters 1.2.2. Phosphotransferase systems 1.2.3. ECF transporter 1.2.4. Transporters/ other
Related categories	transport proteins
Overview on the categories (Excel file) All genes and their categories (Excel file)

ECF transporters are required for the uptake of micronutrients such as cofactors (vitamins), metal ions, or amino acids. The transporters are composed of three general components (membrane spanning T protein und two ATP-hydrolyzing A proteins) and substrate-specific S proteins. In B. subtilis, there are four known substrates for ECF transporters, riboflavin, thiamine, biotin, and tryptophan.

The general components of the ECF transporters

• ybxA ATP-binding A1 protein (EcfA1)
• ybaE ATP-binding A2 protein (EcfA2)
• ybaF membrane-spanning T protein (EcfT)

The substrate-specific S components of the ECF transporters

• RibU: uptake of riboflavin
• ThiT: uptake of thiamine
• YhfU: uptake of biotin
• TrpP: uptake of tryptophan
• YuiG: unknown specificity, may also transport biotin

The class I ECF transporter for thiamine

• ThiU: binding protein
• ThiV: substrate-specific S component
• ThiW: ATP-binding protein (corresponds to A1 + A2)
• ThiX: membrane-spanning T protein