+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Structure-function relationships of integral membrane proteins: membrane transporters vs channels



Structure-function relationships of integral membrane proteins: membrane transporters vs channels



Biopolymers 55(4): 297-307



Escherichia coli lactose permease, a paradigm for membrane transport proteins, and Streptomyces lividans KcsA, a paradigm for K+ channels, are compared on the level of structure, dynamics, and function. The homotetrameric channel, which allows the downhill movement of K+ with an electrochemical gradient, is relatively rigid and inflexible, as observed by Fourier transform infrared spectroscopy. Lactose permease catalyzes transduction of free energy stored in an electrochemical H+ gradient into work in the form of a concentration gradient. In marked contrast to KcsA, the permease exhibits a high degree of H/D exchange, in addition to enhanced sensitivity to lateral lipid packing pressure, thereby indicating that this symport protein is extremely flexible and conformationally active. Finally, the differences between lactose permease and KcsA are discussed in the context of their specific functions with particular emphasis on differences between coupling in symport proteins and gating in channels.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 011411588

Download citation: RISBibTeXText

PMID: 11169921

DOI: 10.1002/1097-0282(2000)55:4<297::aid-bip1003>3.0.co;2-h


Related references

Modeling of the structural features of integral-membrane proteins reverse-environment prediction of integral membrane protein structure (REPIMPS). Protein Science 10(8): 1529-1538, 2001

A feast of membrane protein structures in Madrid. Workshop: Pumps, channels and transporters: structure and function. Embo Reports 2(6): 476-480, 2001

Structure and function of integral membrane proteins of tight junction, claudins. Fukuoka Igaku Zasshi 99(2): 25-31, 2008

Structure and function of integral membrane proteins of tight junction, claudins. 2007

Role of integral membrane proteins in barrier apical membrane function. Journal of the American Society of Nephrology 12(Program and Abstract Issue): 20A, 2001

Membrane transporters for the special amino acid glutamine: structure/function relationships and relevance to human health. Frontiers in Chemistry 2: 61, 2014

Neurotransmitter transporters. A novel family of integral plasma membrane proteins. Febs Letters 307(1): 76-80, 1992

The New York Consortium on Membrane Protein Structure (NYCOMPS): a high-throughput platform for structural genomics of integral membrane proteins. Journal of Structural and Functional Genomics 11(3): 191-199, 2010

Fitting periplasmic membrane fusion proteins to inner membrane transporters: mutations that enable Escherichia coli AcrA to function with Pseudomonas aeruginosa MexB. Journal of Bacteriology 190(2): 691-698, 2008

Integral membrane proteins of the chloroplast envelope: identification and subcellular localization of new transporters. Proceedings of the National Academy of Sciences of the United States of America 99(17): 11487-11492, 2002

Structural biology and structure-function relationships of membrane proteins. Biochemical Society Transactions 47(1): 47-61, 2019

Reconstitution of membrane channels to elucidate couplings between protein function and membrane structure. Biological Chemistry Hoppe-Seyler 367(Suppl.): 38, 1986

HCLCA1 and mCLCA3 are secreted non-integral membrane proteins and therefore are not ion channels. Journal of Biological Chemistry 280(29): 27205-27212, 2005

Dissection of de novo membrane insertion activities of internal transmembrane segments of ATP-binding-cassette transporters: toward understanding topological rules for membrane assembly of polytopic membrane proteins. Molecular Biology of the Cell 9(4): 853-863, 1998

Exploring the role of integral membrane proteins in ATP-binding cassette transporters: analysis of a collection of MalG insertion mutants. Journal of Bacteriology 180(9): 2507-2514, 1998