D- and L-lactate dehydrogenases during invertebrate evolution

BMC Evolutionary Biology. 2008;8(1):268 DOI 10.1186/1471-2148-8-268

 

Journal Homepage

Journal Title: BMC Evolutionary Biology

ISSN: 1471-2148 (Online)

Publisher: BMC

LCC Subject Category: Science: Biology (General): Evolution

Country of publisher: United Kingdom

Language of fulltext: English

Full-text formats available: PDF, HTML

 

AUTHORS

Stillman Jonathon H
Innes David J
Cristescu Melania E
Crease Teresa J

EDITORIAL INFORMATION

Blind peer review

Editorial Board

Instructions for authors

Time From Submission to Publication: 17 weeks

 

Abstract | Full Text

<p>Abstract</p> <p>Background</p> <p>The L-lactate and D-lactate dehydrogenases, which are involved in the reduction of pyruvate to L(-)-lactate and D(+)-lactate, belong to evolutionarily unrelated enzyme families. The genes encoding L-LDH have been used as a model for gene duplication due to the multiple paralogs found in eubacteria, archaebacteria, and eukaryotes. Phylogenetic studies have suggested that several gene duplication events led to the main isozymes of this gene family in chordates, but little is known about the evolution of <it>L-Ldh </it>in invertebrates. While most invertebrates preferentially oxidize L-lactic acid, several species of mollusks, a few arthropods and polychaetes were found to have exclusively D-LDH enzymatic activity. Therefore, it has been suggested that L-LDH and D-LDH are mutually exclusive. However, recent characterization of putative mammalian D-LDH with significant similarity to yeast proteins showing D-LDH activity suggests that at least mammals have the two naturally occurring forms of LDH specific to L- and D-lactate. This study describes the phylogenetic relationships of invertebrate L-LDH and D-LDH with special emphasis on crustaceans, and discusses gene duplication events during the evolution of <it>L-Ldh</it>.</p> <p>Results</p> <p>Our phylogenetic analyses of L-LDH in vertebrates are consistent with the general view that the main isozymes (LDH-A, LDH-B and LDH-C) evolved through a series of gene duplications after the vertebrates diverged from tunicates. We report several gene duplication events in the crustacean, <it>Daphnia pulex</it>, and the leech, <it>Helobdella robusta</it>. Several amino acid sequences with strong similarity to putative mammalian D-LDH and to yeast DLD1 with D-LDH activity were found in both vertebrates and invertebrates.</p> <p>Conclusion</p> <p>The presence of both <it>L-Ldh </it>and <it>D-Ldh </it>genes in several chordates and invertebrates suggests that the two enzymatic forms are not necessarily mutually exclusive. Although, the evolution of <it>L-Ldh </it>has been punctuated by multiple events of gene duplication in both vertebrates and invertebrates, a shared evolutionary history of this gene in the two groups is apparent. Moreover, the high degree of sequence similarity among D-LDH amino acid sequences suggests that they share a common evolutionary history.</p>