Molecular architecture of the recombinant human MCM2-7 helicase in complex with nucleotides and DNA.

DNA replication is a key biological process that involves different protein complexes whose assembly is rigorously regulated in a successive order. One of these complexes is a replicative hexameric helicase, the MCM complex, which is essential for the initiation and elongation phases of replication. After the assembly of a double heterohexameric MCM2-7 complex at replication origins in G1, the 2 heterohexamers separate from each other and associate with Cdc45 and GINS proteins in a CMG complex that is capable of unwinding dsDNA during S phase.

Crystal structure of the open conformation of the mammalian chaperonin CCT in complex with tubulin.

Protein folding is assisted by molecular chaperones. CCT (chaperonin containing TCP-1, or TRiC) is a 1-MDa oligomer that is built by two rings comprising eight different 60-kDa subunits. This chaperonin regulates the folding of important proteins including actin, α-tubulin and β-tubulin.

The U1 snRNP-associated factor Luc7p affects 5' splice site selection in yeast and human.

yLuc7p is an essential subunit of the yeast U1 snRNP and contains two putative zinc fingers. Using RNA-protein cross-linking and directed site-specific proteolysis (DSSP), we have established that the N-terminal zinc finger of yLuc7p contacts the pre-mRNA in the 5' exon in a region close to the cap. Modifying the pre-mRNA sequence in the region contacted by yLuc7p affects splicing in a yLuc7p-dependent manner indicating that yLuc7p stabilizes U1 snRNP-pre-mRNA interaction, thus reminding of the mode of action of another U1 snRNP component, Nam8p.

Expression, purification and crystallization of human CD5 domain III, a nano-scale crystallization example.

The human lymphocyte receptor CD5, a key regulator of immune responses, is involved in the modulation of antigen specific receptor-mediated T cell activation and differentiation signals. CD5 is a membrane glycoprotein which belongs to the group B scavenger receptor cysteine-rich (SRCR) superfamily for which no structural information is available. The most conserved membrane-proximal SRCR domain of CD5 (domain III) has been expressed in HEK-EBNA-293 cells.

Crystal structure of the third extracellular domain of CD5 reveals the fold of a group B scavenger cysteine-rich receptor domain.

Scavenger receptor cysteine-rich (SRCR) domains are ancient protein modules widely found among cell surface and secreted proteins of the innate and adaptive immune system, where they mediate ligand binding. We have solved the crystal structure at 2.2 A of resolution of the SRCR CD5 domain III, a human lymphocyte receptor involved in the modulation of antigen specific receptor-mediated T cell activation and differentiation signals.