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Multidomain truncated hemoglobins: New members of the globin family exhibiting tandem repeats of globin units and domain fusion
Author(s) -
Hade Mangesh Dattu,
Kaur Jagdeep,
Chakraborti Pradip K.,
Dikshit Kanak L.
Publication year - 2017
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1002/iub.1630
Subject(s) - globin , fusion protein , biology , computational biology , tandem repeat , genetics , genome , gene , recombinant dna
Truncated hemoglobins (trHbs) are considered the most primitive members of globin superfamily and traditionally exist as a single domain heme protein in three distinct structural organizations, type I (trHb1_N), type II (trHb2_O) and type III (trHb3_P). Our search of microbial and lower eukaryotic genomes revealed a broad array of multidomain organization, representing multiunit and chimeric forms of trHbs, where multiple units of trHbs are joined together and/or integrated with distinct functional domains. Globin motifs of these multidomain trHbs were from all three groups of trHbs and unambiguously assigned to trHb1_N, trHb2_O and trHb3_P. Multiunit and chimeric forms of trHb1_N were identified exclusively in ciliated protozoan parasites, where multiple units of trHb are integrated in tandem and/or fused with another redox active or signalling domain, presenting an interesting example of gene duplication and fusion in lower eukaryotes. In contrast, trHb2_O and trHb3_P trHbs were found only in bacteria in two or multidomain organization, where amino or carboxy terminus of trHb unit is integrated with different redox‐active or oxidoreductase domains. The identification of these new multiunit and chimeric trHbs and their specific phyletic distribution presents an interesting and challenging finding to explore and understand complex functionalities of these novel multidomain trHbs. © 2017 IUBMB Life, 69(7):479–488, 2017