Structure of a type IV pilus machinery in the open and closed state
نویسندگان
چکیده
Proteins of the secretin family form large macromolecular complexes, which assemble in the outer membrane of Gram-negative bacteria. Secretins are major components of type II and III secretion systems and are linked to extrusion of type IV pili (T4P) and to DNA uptake. By electron cryo-tomography of whole Thermus thermophilus cells, we determined the in situ structure of a T4P molecular machine in the open and the closed state. Comparison reveals a major conformational change whereby the N-terminal domains of the central secretin PilQ shift by ~30 Å, and two periplasmic gates open to make way for pilus extrusion. Furthermore, we determine the structure of the assembled pilus.
منابع مشابه
A Comparison of the effect of open and closed endotracheal suctioning on hemodynamic status of patients in the ICU
Background: If not done properly, suction causes complications such as hypoxia, cardiac arrhythmias or even death. Suction is being used in most hospital wards. Closed Suction appears to have fewer side effects, although studies have reported dissimilar results. Aim: The aim of this study was to compare the effect of open (control) with closed (test) endotracheal suctioning on patients’ Hemodyn...
متن کاملOpen versus closed IV infusion systems: a state based model to predict risk of catheter associated blood stream infections
Objectives To quantify the change in risk of central line associated blood stream infection (CLABSI) following the introduction of a closed infusion container in intensive care units (ICUs) in two Latin American cities. Design A state-space model was used to describe the flow of admissions through the ICU. This approach correctly treats infection as a time-dependent covariate. Results A close...
متن کاملتعیین دقت ثبت ایمپلنت در دو روش تری باز و تری بسته و تعیین ثبت جزئیات سطح دندان حین این قالبگیری
Background and Aims: Accurate recording of implant location is required to achieve passive fit and have the implants without stress concentration. The aim of this in-vitro study was to evaluate the dimensional and angular accuracy of open-tray and closed-tray impression techniques using polyether impression material and also to assess the surface detail reproduction of the tooth while impressio...
متن کاملUptake of extracellular DNA: Competence induced pili in natural transformation of Streptococcus pneumoniae
Transport of DNA across bacterial membranes involves complex DNA uptake systems. In Gram-positive bacteria, the DNA uptake machinery shares fundamental similarities with type IV pili and type II secretion systems. Although dedicated pilus structures, such as type IV pili in Gram-negative bacteria, are necessary for efficient DNA uptake, the role of similar structures in Gram-positive bacteria i...
متن کاملType II protein secretion in Pseudomonas aeruginosa: the pseudopilus is a multifibrillar and adhesive structure.
The type II secretion pathway of Pseudomonas aeruginosa is involved in the extracellular release of various toxins and hydrolytic enzymes such as exotoxin A and elastase. This pathway requires the function of a macromolecular complex called the Xcp secreton. The Xcp secreton shares many features with the machinery involved in type IV pilus assembly. More specifically, it involves the function o...
متن کامل