Uptake of extracellular DNA: Competence induced pili in natural transformation of Streptococcus pneumoniae

Abstract

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 is just beginning to emerge. Recently two essentially very different pilus structures composed of the same major pilin protein ComGC were proposed to be involved in transformation of the Gram-positive bacterium Streptococcus pneumoniae – one is a long, thin, type IV pilus-like fiber with DNA binding capacity and the other one is a pilus structure that was thicker, much shorter and not able to bind DNA. Here we discuss how competence induced pili, either by pilus retraction or by a transient pilus-related opening in the cell wall, may mediate DNA uptake in S. pneumoniae.

A bifunctional ATPase drives tad pilus extension and retraction

“…In prokaryotes the most widespread motor ATPases are secretion motor ATPases that drive the polymerization of protein subunits into extracellular filaments including type II and type IV secretion systems (T2SS or T4SS), competence pili of Gram-positive bacteria, archaeal flagella, and T4P 6,8,11 . Retraction of the fibers of T4SS 12 and T4P 8,13–17 is critical for their function, as is also hypothesized for the T2SS 18 and Gram-positive competence pili 19 . Despite its importance, the retraction mechanism has remained elusive for most of these systems as they possess a single motor ATPase, which is required for fiber extension (Table 1).…”

High-throughput Genome Editing Tools for Lactic Acid Bacteria: Opportunities for Food, Feed, Pharma and Biotech

“…In natural competence, exogenous DNA translocates through a native, genetically encoded DNA uptake machinery formed by a multiprotein complex (Blokesch 2016). It is well-known in Streptococcus (Gardan 2009;Muschiol 2015), but only recently identified and achieved in Lactococcus strains (David 2017;Mulder 2017).…”

Faktor Risiko Manual Handling dengan Keluhan Nyeri Punggung Bawah Pembuat Batu Bata

“…Spasme yang terjadi karena gerakan pinggang yang terlalu mendadak atau berlebihan melampaui kekuatan otot tersebut. Saat mengangkat beban berat dan dalam frekuensi yang lama otot di sekitar lumbosakral memberikan beban yang berat sehingga jika sudah melampaui dari kekuatan otot inilah yang menyebabkan nyeri (Smeltzer & Bare dalam Rinaldi, 2015). Hal tersebut terjadi karena postur tubuh yang tidak ergonomis.…”