Hemoglobins from deep-sea hydrothermal vent scaleworms of the genus Branchipolynoe: A new type of quaternary structure

✍ Scribed by Stéphane Hourdez; François H. Lallier; Brian N. Green; André Toulmond

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 219 KB
• Volume: 34
• Category: Article
• ISSN: 0887-3585
• DOI: 10.1002/(sici)1097-0134(19990301)34:4<427::aid-prot2>3.0.co;2-l

✦ Synopsis

Branchipolynoe symmytilida and B. seepensis are two scaleworms (Polychaeta; Polynoidae) living commensally in the mantle cavity of deep-sea hydrothermal vent and cold-seep mussels. In contrast with littoral members of this family, the two species exhibit a large amount of extracellular hemoglobin (Hb) in their coelomic fluid. Gel filtration revealed the existence of four different Hbs: one minor, high molecular mass (3 10 6 Da) Hb, V1-Hb, reminiscent of a vascular hexagonal bilayer annelid Hb; two major coelomic Hbs, C1-Hb, and C2-Hb, with unusual masses for extracellular annelid Hbs of 153 and 124 kDa respectively; and a minor probably coelomic Hb of 23 kDa (C3-Hb). Using electrospray ionization mass spectrometry, SDS-PAGE after subtilisin treatment, and tandem mass spectrometry, we showed that C1-Hb is a trimer of a 57,996 Da chain and C2-Hb is a dimer of a 57,648 Da chain, each chain being a four-domain/ four-heme polypeptide. This multimeric, multidomain arrangement is unique among annelid Hbs and appears different from that of other known multidomain Hbs. Proteins 1999;34:427-434.