Conformation of abortifacient proteins: trichosanthin, alpha-momorcharin and beta-momorcharin.
The conformations of three abortifacient proteins, trichosanthin from the Chinese herb Tianhuafen and alpha- and beta-momorcharin from the Chinese herb Kuguazi, were studied by circular dichroism. Their spectra in the ultraviolet region (188-250 nm) were similar to each other and also pH-independent (between pH 5 and 9). All three proteins contained about 30% helix, as compared with 39% for trichosanthin by X-ray diffraction study, and 40-60% beta-sheets, but had no beta-turns, suggesting a structural homology among the proteins. The addition of 20 mM sodium dodecyl sulfate nearly doubled the helicity of beta-momorcharin at the expense of beta-sheets but had a small effect on the conformation of alpha-momorcharin, whereas the corresponding change in conformation for trichosanthin was in between the two momorcharins. This implies a marked difference in stability of the three proteins against the surfactant.
S
S
Kubota
H W
HW
Yeung
J T
JT
Yang
D000019:Abortifacient Agents; D000020:Abortifacient Agents, Nonsteroidal; D000596:Amino Acids / Q000032:analysis; D002942:Circular Dichroism; D010940:Plant Proteins; D011487:Protein Conformation; D012269:Ribosomal Proteins; D054788:Ribosome Inactivating Proteins; D015978:Trichosanthin
D000019:Abortifacient Agents; D000020:Abortifacient Agents, Nonsteroidal; D000596:Amino Acids; D010940:Plant Proteins; D012269:Ribosomal Proteins; D015978:Trichosanthin; C039582:MMC protein, Momordica charantia; D054788:Ribosome Inactivating Proteins