| Strcutures of biological macromoleculars always are an important research field of the biological science.The structure resolution of macromeleculars in one side can help the researchers to obtain the three-dimensional structures and to make sense their important function regions in the proteins interior, clarifing the structure basic of the macromoleculars palying role in vivo. On the other hand, the structures of proteins and protein/nuclear acids complexes can make us clearly decipher the mechanisms of proteins and protein /DNA/RNAinteraction. Moreover, the functions of biological macromoleculars can guide and clew the analysis of protein structures. The analysises of the structure will only be the speculation and no evidences of the experiment without the deeply function studies. Therefore, the relationship between the protein structure and function is supplement and intimate each other. In order to elaborate comprehending the relation between them, we prepared the crystal of DPY-30-like C terminal and Musashi1 RRM1 domain and solved their structures.Human DPY-30-like is a homologue of DPY-30 that is an important member of dosage compensation complex in C.elegans. Dosage compensation is a balance mechanism extensive existed in sexual organism that X-linked gene may be diploid amplified expression in XX organism therefore, can cause the tremendous and lethal danger. DPY-30 is likely to be required for the activity of sex-specific dosage compensation factors that down regulate X-linked gene expression in XX. On the other hand, DPY-30-like (homologue of C.elegans) has also been found as a component of histone methyltransferase complexes in yeast, fruit fly and human. In this study, we constructed the DPY-30-like C terminal (55aa), expressed in E.Coli, purified, screened and optimizated the crystal. At last, we obtained the high resolution crystal and sovled its strcure by SAD. The DPY-30-like C terminal exists in dimmer formation and one monomer is consisted of two little flexual helixes linked by a short turn, the dimmer form the typical X type four helix bundle by strong hydrophobic interaction. The extent hydrophobic surface of dimmer might imply that is the platform for DPY-30-like and Ash21 interaction.The other structure solved is an RNA binding protein-Musashi1 RRM1. RNA binding proteins are specific kind of proteins that plays role in the all aspect of RNA transcription including RNA stabliation, RNA alternative splicing, RNA translation and RNA transport by binding to the characteristic DNA or RNA sequence. Musashi1 (Msi1) is an RNA-binding protein expressed in neural stem/progenitor cells, astroglial progenitor cells and astrocytes in the vertebrate central nervous system. It can specific bind to Numb3'-UTR then repress the Notch signal pathway. Musashi1 can active the Notch signal pathway and make the neuron proliferation. Through construction the E.coli expression vector, expression, purification and crystalization , we have obtained the crystal structure of Musashi RRM1 with revolution 1.8 A by molecular replacement method. The Musaahi RRM1 has the typicalβ1α1β2β3α2β4 motif and the hydrophobic surface formed byβ1β3 is important for RNA binding so that the mutants of conserved residues Phe8, Phe48, Phe50 can totally lost their RNA binding abilities in the hydrophobic surface. This can be a clew for Musashi1 and DNA complex crystal in further reseach.In conclusion, the structures of DPY-30-like C terminal and Musashi1 RRM1 domain can make us to understand the relationship between structure and function of proteins.
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