Crystine: fibrous biomolecular material from protein crystals cross-linked in a specific geometry.
Cysteine substitutions were engineered on the surface of maltose binding protein to produce crystine fibers, linear polymers of folded protein formed within a crystal. Disulfide bond formation between adjacent protein molecules within the lattice was monitored by X-ray crystallography. The cross-linked crystals were resistant to dissolution in water or neutral buffer solutions, even though the cross-linking was one-dimensional. However, crystine fibers were observed by transmission electron microscopy to dissociate from the crystals in acidic solutions. Some fibers remained associated as two-dimensional bundles or sheets, with a repeat unit along the fibers consistent with the packing of the individual protein molecules in the crystal. Neutralization of the acidic solutions caused the fibers to re-associate as a solid. Crystine threads were drawn out of this solution. In scanning electron microscopy images, many individual fibers could be seen unwinding from the ends of some threads. Crystine fibers are a new type of biomolecular material with potential applications wherever the use of proteins in a fibrous form is desirable, for example, the incorporation of enzymes into cloth or filtration material.
Srinivasan
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Department of Chemistry, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
Iyer
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Przybycien
T A
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Samsonoff
W A
WA
Bell
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JA
D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D003460:Crystallization; D018360:Crystallography, X-Ray; D058619:Maltose-Binding Proteins; D008854:Microscopy, Electron; D009154:Mutation; D013329:Structure-Activity Relationship
D002352:Carrier Proteins; D058619:Maltose-Binding Proteins