Work

Galactoside-dependent proton transport by mutants of the Escherichia coli lactose carrier

Year: 1989

Type: article

Abstract: Mutations have been introduced into the Escherichia coli lac Y gene by oligonucleotide-directed mutagenesis such that the lactose carrier contains either tyrosine or phenylalanine in place of histidine 322. These mutants did not carry out active accumulation of lactose, melibiose, or methyl-beta-D-galactopyranoside, but facilitated diffusion was still catalyzed. Galactoside-dependent H+ transport, measured with the pH electrode, was retained in both mutants. We conclude that although histidine 322 is important for energy transduction, neither an electronegative atom nor a dissociable proton is essential for proton cotransport with lactose or melibiose.

Source: Journal of Biological Chemistry

DOI: 10.1016/s0021-9258(18)83246-x

Authors: S C King, T H Wilson

Institution: Harvard University

Language: English

Topic: Bacterial Genetics and Biotechnology

Subfield: Genetics

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: hybrid

Estimated APC paid: $3,430

Funders: National Institute of General Medical Sciences, National Institute of Diabetes and Digestive and Kidney Diseases