Venus Flytrap Domain

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As Venus flytrap domain , after English venus flytrap domain also briefly VFT , a special form of is ligand-binding protein domains called, of the same in the two adjacent closing larger areas protein in its tertiary structure as opposed to each other that they can take a ligand intervening with specific binding sites and approach each other when it binds, so that a conformational change of the receptor protein occurs. With a hinge-like movement, the bound molecule, usually an organic acid, is enclosed between the two lobe-shaped domains in a stable form of the protein.

The name was devised in analogy to the capture mode of the Venus flytrap.

Venus flytrap domains are ancient and can be found in many species of archaea and bacteria , where they were first described in 1997. These VFT domains function as substrate-binding proteins (P), which can be loose in the periplasmic space outside of the actual cell membrane . If the substrate has been bound, they can, in the changed, closed form, together with the captured molecule, couple to proteins of the cell membrane, a small (Q) and a larger transmembrane protein (M). The VFT domains then open up and the released substrate enters the cytoplasmic interior via QM - as the protein complex that extends through the membrane - and is thus absorbed into the cell.

Here, an electrochemical Na + gradient is used as the driving force for the transport ( secondary active membrane transport). Unlike ABC transporters , for example , this three-part transport system (P, Q, M) is ATP-independent, which is why it is also called Tripartite ATP-independent Periplasmic transporter or TRAP for short.

Individual evidence

  1. ↑ Stefan Offermanns, Walter Rosenthal (Ed.): Encyclopedic Reference of Molecular Pharmacology . Springer, Berlin / Heidelberg 2004, ISBN 3-540-42843-7 , pp. 962–962 , entry on Venus Flytrap (VFT) Module , doi : 10.1007 / 3-540-29832-0_1729 .
  2. ↑ J. Forward, M. Behrendt, N. Wyborn, R. Cross, D. Kelly: TRAP transporters: a new family of periplasmic solute transport systems encoded by the dctPQM genes of Rhodobacter capsulatus and by homologs in diverse gram-negative bacteria. In: Journal of Bacteriology. Volume 179, No. 17, September 1997, pp. 5482-5493. PMID 9287004 , PMC 179420 (free full text).
  3. ↑ C. Mulligan, E. Geertsma, E. Severi, D. Kelly, B. Poolman, G. Thomas: The substrates-binding protein imposes directionality on to electrochemical sodium gradient-driven TRAP transporter. In: Proc. Natl. Acad. Sci. UNITED STATES. Volume 106, No. 6, February 10, 2009, pp. 1778–1783, doi: 10.1073 / pnas.0809979106 , PMC 2644114 (free full text)