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ABC1, ABC2, ABC3 Superfamilies

as well as the ECF sub-superfamily are all included within the functional ABC superfamily, TC#3.A.1. Their descriptions and constituent families are presented in paragraphs 3 and 4 of the superfamily description under TC#3.A.1. The ABC2 uptake Superfamily includes proteins in TC families 2.A.87 (P-RFT) and 2.A.88 (VUT or ECF).

For efflux systems see: (Wang, B., M. Dukarevich, E.I. Sun, M.R. Yen, and M.H. Saier, Jr. (2009). Membrane porters of ATP-binding cassette transport systems are polyphyletic. J. Membr. Biol. 231: 1-10.) for more details.

For uptake systems see: (Zheng, W.H., A. Västermark, M.A. Shlykov, V. Reddy, E.I. Sun, and M.H. Saier, Jr. (2013). Evolutionary relationships of ATP-Binding Cassette (ABC) uptake porters. BMC Microbiol 13: 98.) for more details.

2.A.87 - The Prokaryotic Riboflavin Transporter (P-RFT) Family
2.A.88 - The Vitamin Uptake Transporter (VUT) Family