Flagellin is a protein that arranges itself in a hollow cylinder to form the filament in bacterial flagellum. Helicobacter pylori ( is a Gram-negative, microaerophilic Bacterium that inhabits various areas of the stomach and Duodenum. Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have A flagellum ( plural flagella) is a tail-like structure that projects from the Cell body of certain Prokaryotic and Eukaryotic cells and it It has a mass of about 30,000 to 60,000 daltons. The unified atomic mass unit ( u) or Dalton ( Da) or sometimes universal mass unit, is an unit of Mass used to express Flagellin is the principal substituent of bacterial flagellum, and is present in large amounts on nearly all flagellated bacteria. A flagellum ( plural flagella) is a tail-like structure that projects from the Cell body of certain Prokaryotic and Eukaryotic cells and it
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Structure
The structure of flagellin is responsible for the helical shape of the flagellar filament, which is important for its proper function. A helix (pl helixes or helices) from the Greek word έλιξ, is a special kind of Space curve, i
The N- and C-termini of flagellin form the inner core of the flagellin protein, and is responsible for flagellin's ability to polymerize into a filament. The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal end, or A polymer is a large Molecule ( Macromolecule) composed of repeating Structural units typically connected by Covalent Chemical bonds The central portion of the protein makes up the outer surface of the flagellar filament. While the termini of the protein is quite similar between all bacterial flagellins, the central portion is wildly variable.
Immune response
In mammals
Mammals often have acquired immune responses (T-cell and antibody responses) to flagellated bacterium occurs frequently to flagellar antigens. Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands An immune system is a collection of mechanisms within an Organism that protects against Disease by identifying and killing Pathogens and Tumor T cells belong to a group of White blood cells known as Lymphocytes, and play a central role in Cell-mediated immunity. Antibodies (also known as immunoglobulins, abbreviated Ig) are Gamma globulin Proteins that are found in Blood or other Bodily Some bacteria are able to switch between multiple flagellin genes in order to evade this response. History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance
The propensity of the immune response to flagellin may be explained by two facts:
- First, flagellin is an extremely abundant protein in flagellated bacteria.
- Secondly, there exists a specific innate immune receptor that recognizes flagellin, Toll-like receptor 5 (TLR5). An immune receptor (or immunologic receptor) is a receptor, usually on a Cell membrane, which binds to a substance (for example a Cytokine) Toll-like receptors ( TLRs) are a class of single membrane-spanning non-catalytic receptors that recognize structurally conserved molecules derived from Microbes Toll-like receptor 5, also known as TLR5, is a human Gene.
In plants
In addition a 22 amino acid sequence (flg22) of the conserved N-terminal part of flagellin is known to activate plant defence mechanisms. Flagellin perception in Arabidopsis thaliana functions via the receptor-like-kinase, FLS2 (flagellin-sensitive-2)). Arabidopsis thaliana ( A-ra-bi-dóp-sis tha-li-á-na; thale cress, mouse-ear cress or Arabidopsis) is a small Mitogen-activated-protein-kinases (MAPK) acts as signalling compounds and more than 900 genes are affected upon flg22 treatment. Mitogen-activated protein (MAP kinases ( are Serine/threonine-specific protein kinases that respond to extracellular stimuli ( Mitogens and regulate various cellular
Pre-stimulation with a synthetic flg22-peptide led to enhanced resistance against bacterial invaders.
External links
More detailed information: Research article: bacterial flagellin and plant disease resistance, published by Zipfel. Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books et al (2004) ) Abstract Article