Aspergillus nidulans has been used extensively as a model organism in the study the nitrate transport protein NrtA, which contributes to the process of nitrate assimilation. Recently, nitrite transporter NitA has been identified in A. nidulans. Nitrite, while not the principal source of nitrogen to organisms, can be used by many bacteria, algae, fungi and plants in certain conditions. The NitA protein is structurally a very different protein when compared directly with the NrtA and NrtB nitrate transporters in A. nidulans; it is half the size with only 6 putative trans-membrane spanning regions. Net nitrite assays using 13N has revealed the kinetic profile for nitrite transport of the WT strain as Km=4.2 Â±1 ÂµM, Vmax = 168Â±21 nmol mg -1 DW-1 h-1. My work concerns the characterisation of the NitA protein in an attempt to assign function to specific amino acid regions using a barrage of site specific mutagenesis; regions have been identified which may be important in substrate translocation.
Full conference title:
9th EUROPEAN CONFERENCE ON FUNGAL GENETICS
- ECFG 9th (2008)