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. Author manuscript; available in PMC: 2022 Aug 6.
Published in final edited form as: J Mol Biol. 2021 Apr 16;433(16):166991. doi: 10.1016/j.jmb.2021.166991

Figure 2. Sequence alignment of Nramp model systems and other clade-representative homologs.

Figure 2.

(a) The Nramp secondary structure displays the characteristic topology of the LeuT fold, with TMs 1–5 and 6–10 comprising the two pseudosymmetric inverted repeats that intertwine in the tertiary structure. * denotes the location of the metal-binding site. TMs 1, 5, 6, and 10 are gold; TMs 3, 4, 8, and 9 are blue; TMs 2, 7, and 11 are gray. The same color scheme is used in later structure and model figures. Some homologs, including most eukaryotic Nramps and EcoleNramp [140], have a 12th TM helix. (b) Comparison of sequence conservation among Nramp model systems and other clade-representative homologs. The percent identity is plotted in the top right of the matrix, and similarity in the bottom left (calculated using the BLOSUM62 scale). (c) Aligned sequences of these model homologs. The numbering and secondary structure of DraNramp are included above the alignment. Key residues for metal binding (magenta asterisks), proton transport and/or voltage dependence (cyan asterisks; blue asterisks indicate additional salt bridge in some homologs), and disease-causing mutation positions discussed in the main text (green highlight) are marked. Sequences were aligned using PSI/TM-Coffee [207] followed by manual editing of the N- and C-termini and some of the gap regions, and the alignment formatted with ESPript [208]. Uniprot accession numbers for the aligned sequences are: DraNramp (Q9RTP8), EcoliNramp (P0A769), Clostridium acetobutylicum MntH (Q97TN5; included as a representative of bacterial clade B), EcoleNramp (E4KPW4), ScaNramp (A0A0S4MEX1), S. cerevisiae Smf1p (C7GUZ9), Arabidopsis NRAMP1 (Q9SAH8), human NRAMP1 (P49279), mouse NRAMP2 (P49282), rat NRAMP2 (O54902), human NRAMP2 (P49281).