Multidomain truncated hemoglobins: New members of the globin family exhibiting tandem repeats of globin units and domain fusion

Hade, Mangesh Dattu; Kaur, Jagdeep; Chakraborti, Pradip K.; Dikshit, Kanak L.

doi:10.1002/iub.1630

Cited by 8 publications

(6 citation statements)

References 48 publications

(64 reference statements)

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“…In mammalian cells, neuroglobin can act as electron donor for cytochrome c (59). In contrast, little is known about the function of hemoglobin in bacteria; suggested roles are nitrosative stress protection and oxygen sensing, binding, and activation (60)(61)(62). In Bacillus subtilis, a truncated hemoglobin efficiently binds and reduces oxygen to water (63).…”

Section: Cable Bacteria Likely Oxidize Sulfide By Reversal Of the Canmentioning

confidence: 99%

On the evolution and physiology of cable bacteria

Kjeldsen

Schreiber

Thorup

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

149

228

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Cable bacteria of the family Desulfobulbaceae form centimeter-long filaments comprising thousands of cells. They occur worldwide in the surface of aquatic sediments, where they connect sulfide oxidation with oxygen or nitrate reduction via long-distance electron transport. In the absence of pure cultures, we used single-filament genomics and metagenomics to retrieve draft genomes of 3 marine Candidatus Electrothrix and 1 freshwater Ca. Electronema species. These genomes contain >50% unknown genes but still share their core genomic makeup with sulfate-reducing and sulfur-disproportionating Desulfobulbaceae, with few core genes lost and 212 unique genes (from 197 gene families) conserved among cable bacteria. Last common ancestor analysis indicates gene divergence and lateral gene transfer as equally important origins of these unique genes. With support from metaproteomics of a Ca. Electronema enrichment, the genomes suggest that cable bacteria oxidize sulfide by reversing the canonical sulfate reduction pathway and fix CO2 using the Wood–Ljungdahl pathway. Cable bacteria show limited organotrophic potential, may assimilate smaller organic acids and alcohols, fix N2, and synthesize polyphosphates and polyglucose as storage compounds; several of these traits were confirmed by cell-level experimental analyses. We propose a model for electron flow from sulfide to oxygen that involves periplasmic cytochromes, yet-unidentified conductive periplasmic fibers, and periplasmic oxygen reduction. This model proposes that an active cable bacterium gains energy in the anodic, sulfide-oxidizing cells, whereas cells in the oxic zone flare off electrons through intense cathodic oxygen respiration without energy conservation; this peculiar form of multicellularity seems unparalleled in the microbial world.

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Section: Cable Bacteria Likely Oxidize Sulfide By Reversal Of the Canmentioning

confidence: 99%

On the evolution and physiology of cable bacteria

Kjeldsen

Schreiber

Thorup

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

149

228

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“…As for the two other families, T globins exist as chimeric and as single domain globins [ 60 ]. Furthermore, multi-unit T globins have been identified in silico , consisting of multiple 2/2 globin repeats [ 61 ]. T1 chimeric and multi-unit globin sequences have been detected in ciliated protozoan parasites, while T1 and T2 single domain globins occur in microbial eukaryotes (ciliates, stramenopiles, oomycetes, opisthokonts, etc.)…”

Section: Genomic Information Reveals Three Globin Familiesmentioning

confidence: 99%

Lessons from the post-genomic era: Globin diversity beyond oxygen binding and transport

et al. 2020

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Vertebrate hemoglobin (Hb) and myoglobin (Mb) were among the first proteins whose structures and sequences were determined over 50 years ago. In the subsequent pregenomic period, numerous related proteins came to light in plants, invertebrates and bacteria, that shared the myoglobin fold, a signature sequence motif characteristic of a 3-on-3 α-helical sandwich. Concomitantly, eukaryote and bacterial globins with a truncated 2-on-2 α-helical fold were discovered. Genomic information over the last 20 years has dramatically expanded the list of known globins, demonstrating their existence in a limited number of archaeal genomes, a majority of bacterial genomes and an overwhelming majority of eukaryote genomes. In vertebrates, 6 additional globin types were identified, namely neuroglobin (Ngb), cytoglobin (Cygb), globin E (GbE), globin X (GbX), globin Y (GbY) and androglobin (Adgb). Furthermore, functions beyond the familiar oxygen transport and storage have been discovered within the vertebrate globin family, including NO metabolism, peroxidase activity, scavenging of free radicals, and signaling functions. The extension of the knowledge on globin functions suggests that the original roles of bacterial globins must have been enzymatic, involved in defense against NO toxicity, and perhaps also as sensors of O 2 , regulating taxis away or towards high O 2 concentrations. In this review, we aimed to discuss the evolution and remarkable functional diversity of vertebrate globins with particular focus on the variety of non-canonical expression sites of mammalian globins and their according impressive variability of atypical functions.

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“…A study of O 2 -binding globin domains in various hemoglobin, myoglobin, and cytoglobin proteins that are encoded by vertebrate genomes implicated the two successive vertebrate WGDs in the evolution of a broad diversity of vertebrate oxygen transport systems [ 327 ]. In addition, various globin proteins have evolved domain fusions and globin domain repeats [ 328 ].…”

Section: Genome Writing By Natural Genetic Engineering—protein Evomentioning

confidence: 99%

Living Organisms Author Their Read-Write Genomes in Evolution

Shapiro

2017

Biology

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Evolutionary variations generating phenotypic adaptations and novel taxa resulted from complex cellular activities altering genome content and expression: (i) Symbiogenetic cell mergers producing the mitochondrion-bearing ancestor of eukaryotes and chloroplast-bearing ancestors of photosynthetic eukaryotes; (ii) interspecific hybridizations and genome doublings generating new species and adaptive radiations of higher plants and animals; and, (iii) interspecific horizontal DNA transfer encoding virtually all of the cellular functions between organisms and their viruses in all domains of life. Consequently, assuming that evolutionary processes occur in isolated genomes of individual species has become an unrealistic abstraction. Adaptive variations also involved natural genetic engineering of mobile DNA elements to rewire regulatory networks. In the most highly evolved organisms, biological complexity scales with “non-coding” DNA content more closely than with protein-coding capacity. Coincidentally, we have learned how so-called “non-coding” RNAs that are rich in repetitive mobile DNA sequences are key regulators of complex phenotypes. Both biotic and abiotic ecological challenges serve as triggers for episodes of elevated genome change. The intersections of cell activities, biosphere interactions, horizontal DNA transfers, and non-random Read-Write genome modifications by natural genetic engineering provide a rich molecular and biological foundation for understanding how ecological disruptions can stimulate productive, often abrupt, evolutionary transformations.

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Multidomain truncated hemoglobins: New members of the globin family exhibiting tandem repeats of globin units and domain fusion

Cited by 8 publications

References 48 publications

On the evolution and physiology of cable bacteria

On the evolution and physiology of cable bacteria

Lessons from the post-genomic era: Globin diversity beyond oxygen binding and transport

Living Organisms Author Their Read-Write Genomes in Evolution

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