Members of the large family of P-type pumps use active transport to maintain gradients of a wide variety of cations across cellular membranes. Recent structures of two P-type pumps at 8-A resolution have revealed the arrangement of transmembrane helices but were insufficient to reveal the architecture of the cytoplasmic domains. However, recent proposals of a structural homology with a superfam...

Geminivirus replication initiator protein (Rep) is a multifunctional viral required for replication. During the process of replication, Rep acts as site- and strand-specific endonuclease, ligase, ATPase, helicase. B' motif β-hairpin loop geminivirus are conserved important Rep-mediated helicase activity To dissect roles various amino acid residues in its unwinding DNA, we investigated eight nea...

The interaction of palytoxin with the Na,K-ATPase was studied by the electrochromic styryl dye RH421, which monitors the amount of ions in the membrane domain of the pump. The toxin affected the pump function in the state P-E2, independently of the type of phosphorylation (ATP or inorganic phosphate). The palytoxin-induced modification of the protein consisted of two steps: toxin binding and a ...

It is known that melanophilin is a myosin Va-targeting molecule that links myosin Va and the cargo vesicles in cells. Here we found that melanophilin directly activates the actin-activated ATPase activity of myosin Va and thus its motor activity. The actin-activated ATPase activity of the melanocyte-type myosin Va having exon-F was significantly activated by melanophilin by 4-fold. Although Rab...

P4-ATPases define a eukaryotic subfamily of the P-type ATPases, and are responsible for transverse flip specific lipids from extracellular or luminal leaflet to cytosolic cell membranes. The enzymatic cycle ATPases is divided into autophosphorylation dephosphorylation half-reactions. Unlike most other transport their substrate during only, i.e. phosphorylation half-reaction not associated with ...

In all kingdoms of life, ATP binding cassette (ABC) transporters are essential to many cellular functions. In this large superfamily of proteins, two catalytic sites hydrolyze ATP to power uphill substrate translocation. A central question in the field concerns the relationship between the two ATPase catalytic sites: Are the sites independent of one another? Are both needed for function? Do the...

In this study we explore the mechanisms by which a double mutation (E59D/D75Y) in cardiac troponin C (CTnC) associated with dilated cardiomyopathy reduces the Ca(2+)-activated maximal tension of cardiac muscle. Studying the single mutants (i.e. E59D or D75Y) indicates that D75Y, but not E59D, causes a reduction in the calcium affinity of CTnC in troponin complex, regulated thin filaments (RTF),...

The widespread second messenger molecule cyclic di-GMP (cdG) regulates the transition from motile and virulent lifestyles to sessile, biofilm-forming ones in a wide range of bacteria. Many pathogenic and commensal bacterial-host interactions are known to be controlled by cdG signaling. Although the biochemistry of cyclic dinucleotide metabolism is well understood, much remains to be discovered ...

IBMPFD/ALS is a genetic disorder caused by single amino acid mutation on the p97 ATPase, promoting ATPase activity and cofactor dysregulation. The disease mechanism underlying malfunction remains unclear. To understand how alters regulation, we assembled full-length p97R155H with its p47 first visualized their structures using single-particle cryo-EM. More than one-third of population was dodec...