Smad proteins are eukarytic transcription regulators in the TGF-beta signaling cascade. Using a combination of sequence and structure-based analyses, we argue that MH1 domain of Smad is homologous to the diverse His-Me finger endonuclease family enzymes. The similarity is particularly extensive with the I-PpoI endonuclease. In addition to the global fold similarities, both proteins possess a co...

Calprotectin (CP) is a transition metal-chelating antimicrobial protein of the calcium-binding S100 family that is produced and released by neutrophils. It inhibits the growth of various pathogenic microorganisms by sequestering the transition metal ions manganese and zinc. In this work, we investigate the manganese-binding properties of CP. We demonstrate that the unusual His(4) motif (site 2)...

The NS5A protein of hepatitis C virus is believed to be an integral part of the viral replicase. Despite extensive investigation, the role of this protein remains elusive. Only limited biochemical characterization of NS5A has been performed, with most research to date involving the myriad of host proteins and signaling cascades that interact with NS5A. The need for better characterization of NS...

Cytoplasmic linker protein (CLIP)-170, CLIP-115, and the dynactin subunit p150(Glued) are structurally related proteins, which associate specifically with the ends of growing microtubules (MTs). Here, we show that down-regulation of CLIP-170 by RNA interference results in a strongly reduced accumulation of dynactin at the MT tips. The NH(2) terminus of p150(Glued) binds directly to the COOH ter...

The highly structured, cis-encoded RNA elements known as riboswitches modify gene expression upon binding a wide range of molecules. The yybP-ykoY motif was one of the most broadly distributed and numerous bacterial riboswitches for which the cognate ligand was unknown. Using a combination of in vivo reporter and in vitro expression assays, equilibrium dialysis, and northern analysis, we show t...

A binding study of nickel ions by a new recombinant human Growth Hormone (hGH), produced as an injected drug, has been done at 27˚C in NaCl solution (50 mM) using an isothermal titration calorimetry. There is a set of three identical and non-interacting binding sites for nickel ions. The intrinsic dissociation equilibrium constant and the molar enthalpy of binding are 40 μM and -16...

A group of highly efficient Zn(II)-dependent RNA-cleaving deoxyribozymes has been obtained through in vitro selection. They share a common motif with the '8-17' deoxyribozyme isolated under different conditions, including different design of the random pool and metal ion cofactor. We found that this commonly selected motif can efficiently cleave both RNA and DNA/RNA chimeric substrates. It can ...