The Structure Research Of Autophagy-related Protein BmAtg8 In Bombyx. Mori And Crystallographic Analysis Of Juvenile Hormone Hpoxide Hydrolase

1. Structural analysis of Bombyx mori Atg8Autophagy is ubiquitous in all the eukaryotes. Signals such as hungry and development can start autophagy, and promote the formation of autophagysome. Autophagosome docks and fuses with the lysosome,then the inner content of the autophagosome are liberated inside the lysosome, consumed by hydrolases and reused by the cell. Silkworm Bombyx mori is an important organism both for economy and academic research. Autophagy is important in the development of silkworm. There are two important ubiquitin like systems in the autophagy (Atg8 - PE system and Atg12 - Atg5 - Atg16 system). In the Atg8 - PE system, the C - terminal arginine of newly synthesized Atg8 is removed by a cysteine protease Atg4, exposuring a glycine residue at the C - terminal. And then Atg7 and Atg3 which are E1 - like and E2 - like enzymes make atg8G to be activated and conjugated to phosphatidylethanolamine (PE) by a covalent bond. The Atg8 - PE system controls the expansion of autophagosome precursor (the phagophore) and directly determines the growth of autophagosomal membranes. Compared with Atg8 in other species, it is showed that Atg8 is conserved in different species range from yeast to mammals. It illustrated that Atg8 plays an important and fundamental role in the cells. Here we report the crystal structure of Atg8 from the silkworm Bombyx mori at 2.40 ? resolution. The space group is P41, unit-cell parameters are a = 96.77, b = 96.77, c = 44.31,α=β=γ= 90°. The core structure of BmAtg8 contains a fourβ- strands (β1 - 4) and flanked by two pairs ofα- helices (α1 - 2 andα3 - 4) on each side.2. Crystallographic analysis of juvenile hormone epoxide hydrolaseJuvenile hormone (JH)is an important hormone that regulates the growth and development of silkworm. JH can prevent the earlier metabolism by ecdysteroids (Ecd), and keep the characters of larvae. Juvenile hormone epoxide hydrolase (JHEH) degradated JH to JH diol. Studying of the structure and function of JHEH could facilitate to illuminate the metabolism of JH in vitro and in vivo. In this paper, JHEH protein was purified and modified by Lys methylation. But the JHEH crystals which we got are still not suitable for X-Ray, and the crystal optimization should be working on.