Role of Ser340 and Thr341 in transmembrane domain IX of the Na+/proline transporter PutP of Escherichia coli in ligand binding and transport

doi:10.1074/jbc.M706741200

HOME

QUICK SEARCH:

	Author:		Keyword(s):
Year:		Vol:		Page:

A more recent version of this article appeared on February 22, 2008

This Article

	Full Text (Accepted Manuscript)
	Supplemental Data
	All Versions of this Article: 283/8/4921 most recent M706741200v1
	Alert me when this article is cited
	Alert me if a correction is posted

Services

	Email this article to a friend
	Similar articles in this journal
	Similar articles in PubMed
	Alert me to new issues of the journal
	Download to citation manager
	Request Permissions

Citing Articles

	Citing Articles via HighWire
	Citing Articles via Google Scholar

Google Scholar

	Articles by Hilger, D.
	Articles by Jung, H.
	Search for Related Content

PubMed

	PubMed Citation
	Articles by Hilger, D.
	Articles by Jung, H.

Social Bookmarking

	What's this?

Papers In Press, published online ahead of print December 21, 2007
J. Biol. Chem, 10.1074/jbc.M706741200
Submitted on August 14, 2007
Revised on December 11, 2007
Accepted on December 21, 2007

Role of Ser340 and Thr341 in transmembrane domain IX of the Na+/proline transporter PutP of Escherichia coli in ligand binding and transport

Daniel Hilger, Maret Bohm, Alexandra Hackmann, and Heinrich Jung

Biology I, Microbiology, LMU Munich, Munich D-80638

Corresponding Author: hjung{at}lmu.de

The Na⁺/solute symporter (SSS) family comprises more than 400 members of pro- and eukaryotic origin. Using the Na⁺/proline transporter PutP of E. coli as a model, the role of two conserved residues, Ser340 and Thr341, is investigated to obtain insights into the mechanism of transport catalyzed by members of this family. Substitution of these amino acids alters the transport kinetics of cells and proteoliposomes containing the PutP variants significantly. In particular, the apparent affinities for Na⁺ and Li⁺ are reduced by two orders of magnitude or more. Also proline binding is affected albeit to a lesser extent than ion binding. Thereby, the presence of a hydroxyl group at position 341 is essential for high affinity ligand binding. Furthermore, Cys placed at position 340 or 341 reacts with sulfhydryl reagents of different polarity indicating accessibility from the water phase. In addition, Cys cross-linking suggests proximity of the residues to other amino acids previously shown to be crucial for ligand binding. For these reasons it is suggested that Ser340 and Thr341 are located in a ligand translocation pathway. Furthermore, it is proposed that the side-chain of Thr341 directly participates in Na⁺ binding.

Add to CiteULike CiteULike Add to Complore Complore Add to Connotea Connotea Add to Del.icio.us Del.icio.us Add to Digg Digg Add to Reddit Reddit Add to Technorati Technorati What's this?

This article has been cited by other articles:

A. Kleefeld, B. Ackermann, J. Bauer, J. Kramer, and G. Unden
The Fumarate/Succinate Antiporter DcuB of Escherichia coli Is a Bifunctional Protein with Sites for Regulation of DcuS-dependent Gene Expression
J. Biol. Chem., January 2, 2009; 284(1): 265 - 275.
[Abstract] [Full Text] [PDF]

S. Faham, A. Watanabe, G. M. Besserer, D. Cascio, A. Specht, B. A. Hirayama, E. M. Wright, and J. Abramson
The Crystal Structure of a Sodium Galactose Transporter Reveals Mechanistic Insights into Na+/Sugar Symport
Science, August 8, 2008; 321(5890): 810 - 814.
[Abstract] [Full Text] [PDF]