Lysozyme 3D structure.

Lysozyme single crystal.

Lysozyme (BE: lysosyme) is an enzyme (EC 3.2.1.17), commonly referred to as the "body's own antibiotic" since it kills bacteria. It is abundantly present in a number of secretions, such as tears. This protein is present in cytoplasmic granules of the polymorphonuclear neutrophils (PMN) and released through the mucosal secretions (such as tears and saliva). They can also be found in high concentration in egg white. Image File history File links Download high resolution version (817x531, 52 KB) Created by uploader from PDB file using SwissPDB viewer. ... Image File history File links Download high resolution version (817x531, 52 KB) Created by uploader from PDB file using SwissPDB viewer. ... Image File history File links Download high resolution version (1280x1024, 161 KB) Single Protein crystal of Lysozyme Photographed by Mathias Klode File links The following pages link to this file: Lysozyme ... Image File history File links Download high resolution version (1280x1024, 161 KB) Single Protein crystal of Lysozyme Photographed by Mathias Klode File links The following pages link to this file: Lysozyme ... Hugo is a masculine name. ... The Entrez logo The Entrez Global Query Cross-Database Search System allows access to databases at the National Center for Biotechnology Information (NCBI) website. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... The National Center for Biotechnology Information (NCBI) is part of the US National Library of Medicine (NLM), which is a branch of the US National Institutes of Health. ... Swiss-Prot is a curated biological database of protein sequences created in 1986 by Amos Bairoch during his PhD and developed by the Swiss Institute of Bioinformatics and the European Bioinformatics Institute. ... The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... Short and long arms Chromosome. ... Chromosome 12 is one of the 23 pairs of chromosomes in humans. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... Staphylococcus aureus - Antibiotics test plate. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Secretion is the process of segregating, elaborating, and releasing chemicals from a cell, or a secreted chemical substance or amount of substance. ... The tear system (click for labels) Tears are a liquid produced by the bodys process of lacrimation to clean and lubricate the eyes. ... Cytoplasm is the viscid, semi-fluid matter contained within the plasma membrane of a cell that helps to hold the cell together. ... Granulocytes are a category of white blood cells, characterised by the fact that all types have differently staining granules in their cytoplasm on light microscopy. ... Mucus is a code word for toby mcdonald. ... Secretion is the process of segregating, elaborating, and releasing chemicals from a cell, or a secreted chemical substance or amount of substance. ... The tear system (click for labels) Tears are a liquid produced by the bodys process of lacrimation to clean and lubricate the eyes. ... Saliva, often informally known as spit, is the moist, clear, and usually somewhat frothy substance produced in the mouths of some animals, including humans. ...

Physiology

Most of the bacteria affected by lysozyme are not pathogenic. In some cases, lysozyme is a primary reason these organisms do not become pathogenic. Lysozyme can act to some extent as an innate opsonin, or as an actively lytic enzyme.

Lysozyme serves as a non-specific innate opsonin by binding to the bacterial surface, reducing the negative charge and facilitating phagocytosis of the bacterium before opsonins from the acquired immune system arrive at the scene. In other words, lysosyme makes it easier for phagocytic white blood cells to engulf bacteria. An opsonin is any molecule that acts as a binding enhancer for the process of phagocytosis, for example, by coating the negatively-charged molecules on the membrane. ... White Blood Cells is also the name of a White Stripes album. ...

The enzyme functions by attacking peptidoglycans (found in the cells walls of bacteria, especially Gram-positive bacteria) and hydrolyzing the bond that connects N-acetyl muramic acid with the fourth carbon atom of N-acetylglucosamine. It does this by binding to the peptidoglycan molecule in the binding site within the prominent cleft between its two domains. This causes the substrate molecule to adopt a strained conformation similar to that of the transition state. The amino acid side chains glutamic acid 35 (Glu35) and aspartate 52 (Asp52) have been found to be critical to the activity of this enzyme. Glu35 acts as a proton donor to the glycosidic bond, cleaving the C-O bond in the substrate, whilst Asp52 acts as a nucleophile to generate a glycosyl enzyme intermediate. The glycosyl enzyme intermediate then reacts with a water molecule, to give the product of hydrolysis and leaving the enzyme unchanged. For further detail see the section on glycoside hydrolases. Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... Peptidoglycan, also known as murein, is a substance that forms a homogeneous layer lying outside the plasma membrane in bacteria. ... Hydrolysis is a chemical reaction or process in which a molecule is split into two parts by reacting with a molecule of water, which has the chemical formula H2O. One of the parts gets an OH- from the water molecule and the other part gets an H+ from the water. ... N-acetyl muramic acid, or MurNAc, is identical to N-acetyl glucosamine (GlcNAc) except that it possesses an additional group (specifically, a propanoic acid molecule with a hydrogen atom on the middle carbon replaced by an oxygen atom to form an ether linkage) attached to Carbon 3, in place of... ... Peptidoglycan, also known as murein, is a substance that forms a homogeneous layer lying outside the plasma membrane in bacteria. ... Glycoside hydrolases (also called glycosidases) catalyze the hydrolysis of the glycosidic linkage to generate two smaller sugars. ...

Role in disease

In some forms of hereditary amyloid, the cause is a mutation in the lysozyme gene, which leads to accumulated lysozyme in several tissues (Mendelian Inheritance in Man (OMIM) 105200). Amyloid describes various types of protein aggregations that share specific traits when examined microscopically. ... In biology, mutations are changes to the genetic material (either DNA or RNA). ... This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ...

Diagnostic use

Lysozyme levels in the blood are often increased in sarcoidosis. Levels are considered raised at 8 mg/l or above.The predictive value for raised ACE level and lysozyme raised level (in combination), for sarcoidosis is up to 83%.

History

Alexander Fleming (1881-1955), the discoverer of penicillin, described lysozyme in 1922.^[1] Alexander Fleming Sir Alexander Fleming (6 August 1881 – 11 March 1955) was a Scottish biologist and pharmacologist. ... Penicillin nucleus Penicillin (sometimes abbreviated PCN) refers to a group of β-lactam antibiotics used in the treatment of bacterial infections caused by susceptible, usually Gram-positive, organisms. ... 1922 (MCMXXII) was a common year starting on Sunday (see link for calendar). ...

Its structure was described by David Chilton Phillips (1924-1999) in 1965 when he got the first 2 angstrom (200 pm) resolution image.^[2][3] This work led Phillips to provide an explanation for how enzymes speed up a chemical reaction in terms of its physical structures. The original mechanism proposed by Phillips was more recently revised.^[4] Lord David Phillips is considered to be a founding father of the now expanding field of structural biology and was an influential figure in science and government. ... An angstrom, angström, or Ã¥ngström (symbol Ã…) is a unit of length. ... Picometre (American spelling: picometer) is an SI measure of length that is equal to 10−12 of a metre. ... Neuraminidase ribbon diagram An enzyme (in Greek en = in and zyme = blend) is a protein, or protein complex, that catalyzes a chemical reaction and also controls the 3D orientation of the catalyzed substrates. ...

Howard Florey (1898-1968) and Ernst B. Chain (1906-1979) also investigated lysozymes. Although they never made much progress in this field, they developed penicillin, which Fleming had failed to do. Howard Walter Florey, Baron Florey, OM, FRS, (September 24, 1898 – February 21, 1968) was a pharmacologist who shared the Nobel Prize for Physiology or Medicine in 1945 with Ernst Boris Chain and Sir Alexander Fleming for his role in the extraction of penicillin. ... Sir Ernst Boris Chain (June 19, 1906 – August 12, 1979) was a German-born British biochemist, and a 1945 co-recipient of the Nobel Prize for Physiology or Medicine for his work on penicillin. ...

References