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Updated: Aug 17, 2026

T-wave Ion Mobility-mass Spectrometry: Basic Experimental Procedures for Protein Complex Analysis
Published on: July 31, 2010
Novel subunit structure observed for noncooperative hemoglobin from Urechis caupo
P R Kolatkar1, W E Meador, R L Stanfield
1Department of Chemistry, University of Texas, Austin 78712.
Abstract:
Tetrameric hemoglobin from the "fat innkeeper" worm Urechis caupo possesses a novel subunit arrangement having an "inside out" quaternary structure in that the G/H helices are located on the outer surface of the tetramer. A 5-A resolution crystal structure reveals that although the individual subunits are beta-like, having a distinct D helix and the general myoglobin fold, the subunit contacts are very different from those previously observed for hemoglobins. Furthermore, the hemoglobin from U. caupo is also quite different from the unusual hemoglobin tetramer from clam which also has its G/H helices on the outer surface but with the hemes in close proximity through E-F helical contacts (Royer, W. E., Jr., Love, W. E., and Fenderson, F. F. (1985) Nature 316, 277-280).
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