NMR analysis of cbEGF domains gives new insights into the structural consequences of a P1148A substitution in fibrillin-1.
Fibrillin-1 is a modular glycoprotein and a major component of the 10-12 nm microfibrils of the extracellular matrix. Mutations in the fibrillin-1 (FBN 1) gene result in the connective tissue disease the Marfan syndrome (MFS) and related disorders. The calcium binding EGF-like (cbEGF) domain is the predominant structural motif of the protein and >70% of mutations leading to MFS disrupt this domain. A missense mutation which changes a proline to alanine (P1148A) in cbEGF domain 13 has been associated with a number of fibrillin disorders including MFS and Shprintzen-Goldberg syndrome. However, it has also been described as a polymorphism. In this study comparative NMR analyses on wild-type and mutant forms of covalently-linked fibrillin cbEGF domain pairs have been performed to investigate the structural consequences of this substitution. A comparison of the two-dimensional NOESY spectra of the wild-type and mutant forms of cbEGF domains 12 & 13 and cbEGF domains 13 & 14 indicated that the proline to alanine amino acid change does not introduce a significant structural defect into cbEGF domain 13 or the adjacent domains and most likely represents a polymorphism. These results demonstrate how, in the case of a protein with a well defined domain organisation such as fibrillin-1, comparative NMR analyses can be used to substantiate genetic evidence for the polymorphic status of an amino acid.
Whiteman
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Sir William Dunn School of Pathology, University of Oxford, UK.
Downing
A K
AK
Handford
P A
PA
D000409:Alanine / Q000737:chemistry; D019943:Amino Acid Substitution; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D004815:Epidermal Growth Factor / Q000737:chemistry*; D000071838:Fibrillin-1; D000071837:Fibrillins; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008840:Microfilament Proteins / Q000737:chemistry* / Q000235:genetics; D011392:Proline / Q000737:chemistry; D011487:Protein Conformation; D054392:Adipokines
D000409:Alanine; D017931:DNA Primers; D004815:Epidermal Growth Factor; D000071838:Fibrillin-1; D000071837:Fibrillins; D008840:Microfilament Proteins; D011392:Proline; C000605722:FBN1 protein, human; D054392:Adipokines