Fibrinogen variant BbetaD432A has normal polymerization but does not bind knob "B".
Bowley, S.R., Lord, S.T.(2009) Blood 113: 4425-4430
- PubMed: 19075185 
- DOI: 10.1182/blood-2008-09-178178
- Primary Citation of Related Structures:  
3E1I - PubMed Abstract: 
Fibrinogen residue Bbeta432Asp is part of hole "b" that interacts with knob "B," whose sequence starts with Gly-His-Arg-Pro-amide (GHRP). Because previous studies showed BbetaD432A has normal polymerization, we hypothesized that Bbeta432Asp is not critic ...