RecJ, a 5' to 3' exonuclease specific for single-stranded DNA, functions in DNA repair and recombination systems. We determined the crystal structure of RecJ bound to Mn(2+) ion essential for its activity. RecJ has a novel fold in which two domains are interconnected by a long helix, forming a central groove. Mn(2+) is located on the wall of the groove and is coordinated by conserved residues c...

Surface texturing is a potential approach to achieving excellent surface performance. To realize high precision and efficiency in micro-texturing fabrication, method utilizing an ultrasonic rolling process proposed. Firstly, the feasibility geometric controllability of micro-texture preparation using are analyzed. Then, contact theory model established, which can describe relationship generatio...

A 17-amino acid arginine-rich peptide from the bovine immunodeficiency virus Tat protein has been shown to bind with high affinity and specificity to bovine immunodeficiency virus transactivation response element (TAR) RNA, making contacts in the RNA major groove near a bulge. We show that, as in other peptide-RNA complexes, arginine and threonine side chains make important contributions to bin...

Recently we reported that the BH3-only proteins Bim and Noxa bind tightly but transiently to the BH3-binding groove of Bak to initiate Bak homo-oligomerization. However, it is unclear how such tight binding can induce Bak homo-oligomerization. Here we report the ligand-induced Bak conformational changes observed in 3D models of Noxa·Bak and Bim·Bak refined by molecular dynamics simulations. In ...

HIV-1 Tat hijacks the human superelongation complex (SEC) to promote proviral transcription. Here we report the 5.9 Å structure of HIV-1 TAR in complex with HIV-1 Tat and human AFF4, CDK9, and CycT1. The TAR central loop contacts the CycT1 Tat-TAR recognition motif (TRM) and the second Tat Zn2+-binding loop. Hydrogen-deuterium exchange (HDX) shows that AFF4 helix 2 is stabilized in the TAR comp...

Grooved terrain is subdivided on the basis of pervasive morphology into (!) groove lanes elongate parallel groove bands, (2) grooved polygons polygonal domains ofparallel grooves, (3) reticulate rrain polygonal domains of orthogonal grooves, and (4) complex grooved terrain polygons with several complexly cross-cutting groove sets. Detailed geologic mapping ofselect areas, employing previously e...