Engineering of betabellin-15D: a 64 residue beta sheet protein that forms long narrow multimeric fibrils.
The betabellin target structure is a beta-sandwich protein consisting of two 32 residue beta-sheets packed against one another by interaction of their hydrophobic faces. The 32 residue chain of betabellin-15S (HSLTAKIpkLTFSIAphTYTCAV pkYTAKVSH, where p=DPro, k=DLys, and h=DHis) did not fold in water at pH 6.5. Air oxidation of betabellin-15S provided betabellin-15D, the 64 residue disulfide bridged two-chain molecule, which also remained unfolded in water at pH 6.5. By circular dichroic spectropolarimetry, the extent of beta structure observed for betabellin-15D increased with the pH and ionic strength of the solution and the betabellin-15D concentration. By electron microscopy, in 5.0 mM MOPS and 0.25 M NaCl at pH 6.9, betabellin-15D formed long narrow multimeric fibrils. A molecular model was constructed to show that the dimensions of these betabellin-15D fibrils are consistent with a single row of beta-sandwich molecules joined by multiple intersheet H-bonds.
Lim
A
A
Department of Chemistry, The University of North Carolina at Chapel Hill, 27599-3290, USA.
Saderholm
M J
MJ
Makhov
A M
AM
Kroll
M
M
Yan
Y
Y
Perera
L
L
Griffith
J D
JD
Erickson
B W
BW
D000595:Amino Acid Sequence; D001665:Binding Sites; D002498:Centrifugation; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D003300:Copper / Q000378:metabolism; D004220:Disulfides; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry; D008854:Microscopy, Electron; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009994:Osmolar Concentration; D010455:Peptides; D011487:Protein Conformation; D011489:Protein Denaturation; D015202:Protein Engineering; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification; D011994:Recombinant Proteins
D004220:Disulfides; D010455:Peptides; D011506:Proteins; D011994:Recombinant Proteins; C114710:betabellin 12; C114709:betabellin 15; C089955:betabellin 14; D003300:Copper