RESUMO
The CK1 family kinases regulate multiple cellular aspects and play important roles in Wnt/Wingless and Hedgehog signalling. The kinase domain of Drosophila Gilgamesh isoform I (Gilgamesh-I), a homologue of human CK1-γ, was purified and crystallized. Crystals of methylated Gilgamesh-I kinase domain with a D210A mutation diffracted to 2.85â Å resolution and belonged to space group P43212, with unit-cell parameters a = b = 52.025, c = 291.727â Å. The structure of Gilgamesh-I kinase domain, which was determined by molecular replacement, has conserved catalytic elements and an active conformation. Structural comparison indicates that an extended loop between the α1 helix and the ß4 strand exists in the Gilgamesh-I kinase domain. This extended loop may regulate the activity and function of Gilgamesh-I.
Assuntos
Caseína Quinase I/química , Proteínas de Drosophila/química , Drosophila melanogaster/metabolismo , Sequência de Aminoácidos , Animais , Caseína Quinase I/genética , Caseína Quinase I/metabolismo , Cristalização , Cristalografia por Raios X , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Mutação/genética , Conformação Proteica , Estrutura Terciária de Proteína , Homologia de Sequência de AminoácidosRESUMO
Proliferating cell nuclear antigen (PCNA) plays essential roles in DNA replication, DNA repair, cell-cycle regulation and chromatin metabolism. The PCNA from Drosophila melanogaster (DmPCNA) was purified and crystallized. The crystal of DmPCNA diffracted to 2.0 Å resolution and belonged to space group H3, with unit-cell parameters a = b = 151.16, c = 38.28 Å. The structure of DmPCNA was determined by molecular replacement. DmPCNA forms a symmetric homotrimer in a head-to-tail manner. An interdomain connector loop (IDCL) links the N- and C-terminal domains. Additionally, the N-terminal and C-terminal domains contact each other through hydrophobic associations. Compared with human PCNA, the IDCL of DmPCNA has conformational changes, which may explain their difference in function. This work provides a structural basis for further functional and evolutionary studies of PCNA.