Τίτλος:
Specificity profile of NAT/NCS2 purine transporters in Sinorhizobium (Ensifer) meliloti
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
Sinorhizobium (Ensifer) meliloti is a model example of a soil alpha-proteobacterium which induces the formation of nitrogen-fixing symbiotic nodules on the legume roots. In contrast to all other rhizobacterial species, S. meliloti contains multiple homologs of nucleobase transporter genes that belong to NAT/NCS2 family (Nucleobase-Ascorbate Transporter/Nucleobase-Cation Symporter-2). We analyzed functionally all (six) relevant homologs of S. meliloti 1,021 using Escherichia coli K-12 as a host and found that five of them are high-affinity transporters for xanthine (SmLL9), uric acid (SmLL8, SmLL9, SmX28), adenine (SmVC3, SmYE1), guanine (SmVC3), or hypoxanthine (SmVC3). Detailed analysis of substrate profiles showed that two of these transporters display enlarged specificity (SmLL9, SmVC3). SmLL9 is closely related in sequence with the xanthine-specific XanQ of E. coli. We subjected SmLL9 to rationally designed site-directed mutagenesis and found that the role of key binding-site residues of XanQ is conserved in SmLL9, whereas a single amino-acid change (S93N) converts the xanthine/uric-acid transporter SmLL9 to a xanthine-preferring variant, due to disruption of an essential hydrogen bond with the C8 oxygen of uric acid. The results highlight the presence of several different purine nucleobase transporters in S. meliloti and imply that the purine transport might be important in the nodule symbiosis involving S. meliloti. © 2020 John Wiley & Sons Ltd
Συγγραφείς:
Botou, M.
Yalelis, V.
Lazou, P.
Zantza, I.
Papakostas, K.
Charalambous, V.
Mikros, E.
Flemetakis, E.
Frillingos, S.
Περιοδικό:
Molecular Microbiology
Εκδότης:
Wiley-Blackwell Publishing Ltd
Λέξεις-κλειδιά:
adenine transporter; amino acid transporter; bacterial DNA; guanine transporter; hypoxanthine transporter; unclassified drug; urate transporter; adenine; carrier protein; cotransporter; guanine; hypoxanthine; uric acid; xanthine, amino acid substitution; Article; bacterial gene; bacterial growth; binding site; Bradyrhizobium; carboxy terminal sequence; controlled study; disulfide bond; Escherichia coli K-12; gene amplification; gene sequence; hydrogen bond; hydrophobicity; Mesorhizobium; molecular cloning; molecular dynamics; multilocus sequence typing; NCS2 gene; nonhuman; phylogenetic tree; phylogeny; priority journal; protein analysis; protein binding; protein expression; protein function; protein stability; protein transport; Rhizobium tropici; sequence alignment; sequence analysis; sequence homology; Sinorhizobium meliloti; site directed mutagenesis; symbiosis; active transport; genetics; metabolism; microbiology; nodulation; physiology; rhizosphere; Sinorhizobium meliloti, Adenine; Biological Transport, Active; Escherichia coli K12; Guanine; Hypoxanthine; Membrane Transport Proteins; Plant Root Nodulation; Rhizosphere; Root Nodules, Plant; Sinorhizobium meliloti; Symporters; Uric Acid; Xanthine
