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Nerve Globins in Invertebrates

Nerve Globins in Invertebrates The expression of nerve hemoglobins in invertebrates is a well‐established fact, but this occurrence is uncommon. In the species where nerve globins occur, they probably function as an oxygen store for sustaining activity of the nerves during anoxic conditions. Although invertebrate nerve globins are functionally similar with respect to O2 affinity, they are by no means uniform in structure and can differ in size, cellular localization and heme‐coordination. The best‐studied nerve globin is the mini‐globin of Cerebratulus lacteus, which belongs to a class of globins containing the polar TyrB10/GlnE7 pair in the distal pocket. The amide and phenol side chains normally cause low rates of O2 dissociation and ultra‐high O2 affinity by forming strong hydrogen bonds with bound ligands. Cerebratulus hemoglobin, however, has a moderate O2 affinity, due to the presence of a third polar amino‐acid in its active site, ThrE11, which inhibits hydrogen bonding to bound oxygen by the B10 tyrosine side chain. IUBMB Life, 56: 653‐656, 2004 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png IUBMB Life Wiley

Nerve Globins in Invertebrates

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References (1)

Publisher
Wiley Subscription Services, Inc., A Wiley Company
Copyright
Copyright © 2004 International Union of Biochemistry and Molecular Biology
ISSN
1521-6543
eISSN
1521-6551
DOI
10.1080/15216540500037471
pmid
15804828
Publisher site
See Article on Publisher Site

Abstract

The expression of nerve hemoglobins in invertebrates is a well‐established fact, but this occurrence is uncommon. In the species where nerve globins occur, they probably function as an oxygen store for sustaining activity of the nerves during anoxic conditions. Although invertebrate nerve globins are functionally similar with respect to O2 affinity, they are by no means uniform in structure and can differ in size, cellular localization and heme‐coordination. The best‐studied nerve globin is the mini‐globin of Cerebratulus lacteus, which belongs to a class of globins containing the polar TyrB10/GlnE7 pair in the distal pocket. The amide and phenol side chains normally cause low rates of O2 dissociation and ultra‐high O2 affinity by forming strong hydrogen bonds with bound ligands. Cerebratulus hemoglobin, however, has a moderate O2 affinity, due to the presence of a third polar amino‐acid in its active site, ThrE11, which inhibits hydrogen bonding to bound oxygen by the B10 tyrosine side chain. IUBMB Life, 56: 653‐656, 2004

Journal

IUBMB Life – Wiley

Published: Nov 1, 2004

Keywords: Nerve globins; invertebrates; oxygen affinity

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