Structure/function relationship of the Chlorella glucose/H+ symporter.

Caspari T, Stadler R, Sauer N, Tanner W (1994)

Publication Language: English

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 1994

Journal

Journal of Biological Chemistry American Society for Biochemistry and Molecular Biology

Book Volume: 269

Pages Range: 3498-3502

Journal Issue: 5

Open Access Link: http://www.jbc.org/content/269/5/3498.long

Abstract

The Clorella kessleri HUP 1 gene coding for a hexose/H+ symporter has been expressed in a glucose uptake-deficient mutant of Schizosaccharomyces pombe. The transformants are able to grow on glucose and to accumulate 3-O-methylglucose 100-fold. This system has been used to test the activity of specifically mutated HUP 1 cDNAs. All three histidyl residues were exchanged with arginine (H73R, H170R, and H495R) without a major effect on transport activity. When Asp-44 within the first transmembrane helix was replaced by Asn, the transporter was inactive; replacement by Glu (D44E) resulted in a loss of activity by 90% and a 15-fold increased Km value. Glutamine residues conserved in all glucose transporters sequenced so far were exchanged: Q179N (in helix 5), Q298G and Q299N (both in helix 7). Whereas Q298G only resulted in a small Km change, both Q179N and Q299N showed an increase in Km by a factor of 10. Inserting 4 additional amino acids each into the two largest loops (1 and 6) reduced the activity dramatically; only in the latter case this was due to decreased protein synthesis or stability. Two COOH-terminal deletions (-27 and -43 amino acids) were also tested. The 27 COOH-terminal amino acids, but not the 43 COOH-terminal amino acids, could be removed without affecting transporter activity.

Authors with CRIS profile

Ruth Stadler Lehrstuhl für Molekulare Pflanzenphysiologie Norbert Sauer Lehrstuhl für Molekulare Pflanzenphysiologie

Involved external institutions

Universität Regensburg DE Germany (DE)

How to cite

APA:

Caspari, T., Stadler, R., Sauer, N., & Tanner, W. (1994). Structure/function relationship of the Chlorella glucose/H+ symporter. Journal of Biological Chemistry, 269(5), 3498-3502.

MLA:

Caspari, Thomas, et al. "Structure/function relationship of the Chlorella glucose/H+ symporter." Journal of Biological Chemistry 269.5 (1994): 3498-3502.

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