6533b7d8fe1ef96bd126a3ce
RESEARCH PRODUCT
Respiratory proteins in Sipunculus nudus--implications for phylogeny and evolution of the hemerythrin family.
Bernhard LiebAchim Meyersubject
NematodaPhysiologymedicine.medical_treatmentBiochemistryHemerythrinEvolution MolecularPhylogeneticsSipunculus nudusmedicineAnimalsProtein IsoformsMolecular BiologyPhylogenySipunculaExpressed Sequence TagsExpressed sequence tagLikelihood FunctionsAnnelidPhylogenetic treebiologyRespirationHemocyaninBayes TheoremAnatomybiology.organism_classificationHemerythrinBiochemistryGene Expression RegulationMultigene Familydescription
Three major classes of respiratory proteins are known, hemoglobin, molluscan and arthropod hemocyanin, and hemerythrin (Hr). Similar to hemoglobin, respiratory Hr is packed into erythrocytes floating in the coelomic fluid and is only known from sipunculids, brachiopods, and priapulids. Owing to this scattered distribution, the presence of Hr is generally assumed to be the plesiomorphic condition without phylogenetic importance. By sequencing 2000 Expressed Sequence Tags (ESTs) from Sipunculus nudus, we found 75 Hr-coding ESTs assembled to 20 cDNA contigs classified as four distinct Hr isoforms: three polymeric Hrs (subunit A, A', and B) and the monomeric myo-hemerythrin (myoHr). Phylogenetic analyses revealed a clade of annelid and sipunculan monomeric Hrs, distinct from polymeric Hrs. Monomeric Hrs from annelids and sipunculids can be clustered together using Maximum Likelihood tree-building and network analyses, as well as applying Bayesian methods. Three distinct Hr clusters were found for S. nudus, suggesting a new monomeric Hr isoform.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2009-07-16 | Comparative biochemistry and physiology. Part B, Biochemistrymolecular biology |