Replicative DNA polymerases are multiprotein machines that are tethered to DNA during chain extension by sliding clamp proteins. The clamps are designed to encircle DNA completely, and they are manipulated rapidly onto DNA by the ATP-dependent activity of a clamp loader. We outline the detailed mechanism of gamma complex, a five-protein clamp loader that is part of the Escherichia coli replicas...

The Escherichia coli clamp loader, gamma complex (gamma(3)deltadelta'lambdapsi), catalyzes ATP-driven assembly of beta clamps onto primer-template DNA (p/tDNA), enabling processive replication. The mechanism by which gamma complex targets p/tDNA for clamp assembly is not resolved. According to previous studies, charged/polar amino acids inside the clamp loader chamber interact with the double-s...

Chromosome replication relies on sliding clamps that are loaded by energy-dependent complexes. In Escherichia coli, the ATP-binding clamp loader subunit DnaX exists as both long (τ) and short (γ) forms generated through programmed translational frameshifting, but the need for both forms is unclear. Here, we show that in Caulobacter crescentus, DnaX isoforms are unexpectedly generated through pa...

Sliding clamps are toroidal proteins that encircle DNA and act as mobile platforms for DNA replication and repair machinery. To be loaded onto DNA, the eukaryotic sliding clamp Proliferating Cell Nuclear Antigen (PCNA) must be splayed open at one of the subunit-subunit interfaces by the ATP-dependent clamp loader, Replication Factor C, whose clamp-interacting sites form a right-handed spiral. E...

Traditional online wheel-set ultrasonic inspection method and inspection technology can not meet the new requirement of High Power Locomotive wheel-set online. In this article, features of locomotive wheel and defect distribution are analyzed, and a more strictly online inspection requirement is put forward. Based on which, an optimized multi arrangement of phased array and conventional ultraso...

the tire-mechanics models have been developed for the study of wheel movement on the road or soil surface while these models are unlikely to describe the motion of wheels on uneven surfaces. due to dynamical complexity of this phenomena and the importance of this subject for farm conditions and the wheel carrier devices, the present research aimed to investigate the effects of several parameter...

In this paper, an innovative mobile platform is presented which is equipped by three new wheels. The core of the new idea is to establish a new design of rigid circular structure which can be implemented as a wheel by variable radius. The structure of wheel includes a circular pattern of a simple two-link mechanism assembled to obtain a wheel shape. Each wheel has two degrees of freedom. The fi...

in this paper, an innovative mobile platform is presented which is equipped by three new wheels. the core of the new idea is to establish a new design of rigid circular structure which can be implemented as a wheel by variable radius. the structure of wheel includes a circular pattern of a simple two-link mechanism assembled to obtain a wheel shape. each wheel has two degrees of freedom. the fi...

apart from regular wheel wear such as decreasing wheel diameters and reduced flange thicknesses and heights, wheel flats (wf) and oval wheels (or oor, out-of-roundness) are the most common wheelset problems for railway vehicles. within the fp7 research project “saferail”, apt has developed an innovative wheelset monitoring system so-called “wheel flat and out of roundness monitoring (worm) syst...