Functional characterization of the nucleobase-ascorbate transporter family of Arabidopsis thaliana
Abstract
The Nucleobase-Ascorbate Transporter (NAT) family is ubiquitous among organisms. However, the solute transport specificity differs among NATs across evolutionary space. It is important to study the NAT family to gain evolutionary and structure-function insight for the rational design of antifungal and antibacterial drugs. The Arabidopsis thaliana genome contains 12 putative members of the NAT family, whose functions have previously eluded discovery. Radiolabeled uptake studies of AtNAT1 through AtNAT8 via heterologous expression in Saccharomyces cerevisiae strains deficient in native nucleobase transport revealed transport profiles for each AtNAT. A substrate specificity of xanthine, adenine, guanine and hypoxanthine was revealed for AtNAT3. Radiolabeled uptake studies utilizing an Arabidopsis thaliana AtNAT3 T-DNA knockout mutant supported xanthine transport. This work functionally characterizes 8 more NAT members and identifies novel and distinct specificity profiles for each AtNAT, despite high sequence similarity, greatly adding to the structure-function information available for this ubiquitous family.
Degree
M.S.
Advisors
Mourad, Purdue University.
Subject Area
Biology|Plant biology|Genetics
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