Calcium effect and pH-dependence on self-association and structural stability of the Apis mellifera major royal jelly protein 1

Abstract

-The major royal jelly protein 1 (MRJP1) is the main glycoprotein in honey bee royal jelly. In brain tissues, MRJP1 is found in intercellular spaces and associated to cytoskeleton within cells. MRJP1 must be involved in multiple biological functions, yet there is a lack of structural information on the protein. MRJP1 was herein purified from royal jelly and characterized through electrophoresis and mass spectrometry as the same protein found in cerebral tissue. Unfolding curves obtained by circular dichroism analyses strongly suggest its high stability under different pHs. However, calcium ions made MRJP1 susceptible to temperature and pH effects. In the presence of 2 mM calcium, very high stabilities were achieved at pH 6.0 and 7.0 with ΔG 25 over 62 kJ mol −1 . Overall, the present results represent a valuable effort aimed at the structural characterization of MRJP1, representing an essential step toward the determination of its roles in honey bee neural processes.MRJP1 / Apis mellifera / protein stability / mass spectrometry / circular dichroism

Origin and function of the major royal jelly proteins of the honeybee (Apis mellifera) as members of the yellow gene family

“…Recently Cruz et al (2011) determined the secondary structure content of MRJP1 via circular dichroism (CD) measurements to consist of 9.6% α-helices, 38.3% βsheets and 20% β-turns. Recently Cruz et al (2011) determined the secondary structure content of MRJP1 via circular dichroism (CD) measurements to consist of 9.6% α-helices, 38.3% βsheets and 20% β-turns.…”

“…Recently Cruz et al (2011) determined the secondary structure content of MRJP1 via circular dichroism (CD) measurements to consist of 9.6% α-helices, 38.3% βsheets and 20% β-turns. In the oligomer of 280/90 kDa five non-covalently bonded MRJP1 molecules build a complex with one molecule of apisimin, a 5.5 kDa protein of RJ (Tamura et al, 2009a,b;Cruz et al, 2011). MRJP1 is able to form oligomeric complexes of 280/90, 340 or 420 kDa (Šimúth, 2001;Tamura et al, 2009b;Cruz et al, 2011).…”

Characterizing the Structure and Oligomerization of Major Royal Jelly Protein 1 (MRJP1) by Mass Spectrometry and Complementary Biophysical Tools

“…20 Isoelectric focusing reveals the presence of nine MRJP1 isoforms that share a similar MW but have slightly different pIs between 4.7 and 5.2. 21,22 Differences in the nature and extent of post-translational modifications are thought to be chiefly responsible for this heterogeneity. 9 …”

“…Chromatographic, electrophoretic, and light scattering studies yielded size estimates of 280–420 kDa for these MRJP1/apisimin assemblies. 11,22,26 Binding is mediated solely by noncovalant interactions, as intermolecular disulfide bridges are absent. 28 …”

Determination of amino acids and protein content in fresh and commercial royal jelly from Bulgaria

“…Royal jelly (RJ) is a secretion produced in the hypopharyngeal and mandibular glands, located in the heads of young worker honey bees Apis mellifera L. [1,2]. It is fed to all bee larvae for three days and to queen larvae for all her life, and it plays a key role in honey bee caste determination [3][4][5].…”