Physiological and biochemical characterization of AnNitA, the Aspergillus nidulans high-affinity nitrite transporter.
High-affinity nitrite influx into mycelia of Aspergillus nidulans has been characterized by use of (13)NO(2)(-), giving average K(m) and V(max) values of 48 ± 8 μM and 228 ± 49 nmol mg(-1) dry weight (DW) h(-1), respectively. Kinetic analysis of a plot that included an additional large number of low-concentration fluxes gave an excellent monophasic fit (r(2) = 0.96), with no indication of sigmoidal kinetics. Two-dimensional (2D) and three-dimensional (3D) models of AnNitA are presented, and the possible roles of conserved asparagine residues N122 (transmembrane domain 3 ]Tm 3]), N173 (Tm 4), N214 (Tm 5), and N246 (Tm 6) are discussed.
School of Biology, University of St. Andrews, St. Andrews, Fife, United Kingdom.
Shiela E
SE
Unkles
Vicki F
VF
Symington
Zorica
Z
Kotur
Ye
Y
Wang
M Yaeesh
MY
Siddiqi
James R
JR
Kinghorn
Anthony D M
AD
Glass
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001233:Aspergillus nidulans / Q000254:growth & development / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D017124:Conserved Sequence; D005656:Fungal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D026901:Membrane Transport Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009573:Nitrites / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D005656:Fungal Proteins; D026901:Membrane Transport Proteins; D009573:Nitrites