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T-wave Ion Mobility-mass Spectrometry: Basic Experimental Procedures for Protein Complex Analysis
Published on: July 31, 2010
Interface sliding as illustrated by the multiple quaternary structures of liganded hemoglobin
T C Mueser1, P H Rogers, A Arnone
1Department of Biochemistry, College of Medicine, The University of Iowa, Iowa City, Iowa 52242, USA.
Biochemistry
|December 12, 2000
Summary
Fully liganded hemoglobin exhibits multiple quaternary structures, not just one. The dimer-dimer interface allows sliding, suggesting broader roles in protein assemblies.
Area of Science:
- Structural biology
- Biochemistry
- Protein dynamics
Background:
- Mammalian hemoglobin was thought to have a single quaternary structure (R structure) when fully liganded.
- Recent studies identified a second quaternary structure (R2 structure) for liganded hemoglobin.
- Both R and R2 structures are energetically accessible and coexist in solution.
Purpose of the Study:
- To investigate the energetic accessibility of other quaternary structures for liganded hemoglobin.
- To explore the structural flexibility of the dimer-dimer interface in hemoglobin.
Main Methods:
- Determined and refined three crystal structures of bovine carbonmonoxyhemoglobin.
- Utilized crystallographic methods to analyze quaternary structures.
Main Results:
- Provided evidence for a wide range of energetically accessible structures at the dimer-dimer interface of liganded hemoglobin.
- Demonstrated that these structures are related by a simple sliding motion.
- Characterized the dimer-dimer interface as a 'molecular slide bearing'.
Conclusions:
- The dimer-dimer interface of liganded hemoglobin is flexible and allows for sliding motions between alpha beta dimers.
- This interface flexibility likely plays significant structural and functional roles in hemoglobin and potentially other protein assemblies.
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