Crystal structure of vitelline membrane outer layer protein I (VMO-I): a folding motif with homologous Greek key structures related by an internal three-fold symmetry.
The crystal structure of vitelline membrane outer layer protein I (VMO-I), which is isolated from the vitelline membrane outer layer of hen's eggs, has been determined by the multiple isomorphous replacement method and refined to an R-factor of 18.8% at 2.2 A resolution. The main chain folds into an unusual structure that consists of three beta-sheets forming Greek key motifs, which are related by an internal pseudo three-fold symmetry. The internal portion surrounded by these three beta-sheets is filled with hydrophobic side chains. This conformational feature coincides with three internal repeats in the sequence. Although a similar fold exists in the second domain of delta-endotoxin, there are significant structural differences between the two proteins, with the three-fold symmetry being most regular in VMO-I.
Shimizu
T
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Protein Engineering Research Institute, Osaka, Japan.
Vassylyev
D G
DG
Kido
S
S
Doi
Y
Y
Morikawa
K
K
D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D004527:Egg Proteins / Q000737:chemistry* / Q000302:isolation & purification; D005260:Female; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017510:Protein Folding; D017433:Protein Structure, Secondary; D014817:Vitelline Membrane / Q000737:chemistry*
D004527:Egg Proteins; C035651:vitelline membrane proteins