Abstract:

MRJP1 is one of the most important members in the Major Royal Jelly Proteins (MRJPs) family with monomeric
and oligomeric forms in royal jelly. In order to investigate the secondary structure of RJP1 oligomer, MRJP1 oligomer was
extracted from fresh royal jelly and purified by ToyoScreen GigaCap Q-650M anion exchange column, then identified by
sedimentation equilibrium and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Afterwards,
we detected MRJP1 oligomer by synchrotron radiation circular dichroism (SRCD) to clarify the correlation between
its secondary structure and different concentration of Ca2+ (10, 50 and 200 mmol/L). In addition, its Tm value was also
determined. The results showed that the proportion of β-strand (about 55%) was the highest, followed in decreasing order
by random coil (20%) and α-helix (15%) and β-turns (10%). Ca2+ had little effect on the secondary structure of MRJP1
oligomer. The Tm value of MRJP1 oligomer was 55 ℃. To conclude, a new method for the purification of MRJP1 oligomer
and information on its secondary structure have been presented in this study.

Key words: royal Jelly, MRJP1, purification, circular dichroism (CD)