Information about Beta Helix
A beta helix is a protein structure formed by the association of parallel beta strands in a helical pattern with either two or three faces. The structure is stabilized by inter-strand hydrogen bonds, protein-protein interactions, and sometimes bound metal ions. Both left- and right-handed beta helices have been identified.
. Known three-stranded helices are appreciably longer than their two-stranded counterparts.
The first beta-helix was observed in the enzyme pectate lyase, which contains a seven-turn helix that reaches 34 Å (3.4 nm) long. The P22 phage tailspike protein, a component of the P22 bacteriophage, has 13 turns and in its assembled homotrimer is 200 Å (20 nm) in length. Its interior is close-packed with no central pore and contains both hydrophobic residues and charged residues neutralized by salt bridges.
Both pectate lyase and P22 tailspike protein contain right-handed helices; left-handed versions have been observed in enzymes such as UDP-N-acetylglucosamine acyltransferase and archaeal carbonic anhydrase. Other proteins that contain beta helices include the antifreeze proteins from the beetle Tenebrio molitor (right-handed) and from the spruce budworm, Choristoneura fumiferana (left-handed), where regularly spaced threonines on the β-helices bind to the surface of ice crystals and inhibit their growth.
Beta helices can associate with each other effectively, either face-to-face (mating the faces of their triangular prisms) or end-to-end (forming hydrogen bonds). Hence, β-helices can be used as "tags" to induce other proteins to associate, similar to coiled coil segments.
Glycine (abbreviated as Gly or G)[1] is the organic compound with the formula HO2CCH2NH2.
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A structural domain is an element of overall structure within a protein that is self-stabilizing and often folds independently of the rest of the protein chain.
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Two-stranded helices
The simplest beta helix contains two "layers" of beta sheets connected by glycine-rich six-residue loops that invariably contain an aspartate to bind one calcium ion per loop. Each layer consists of a nearly-planar series of parallel hydrogen-bonded beta strands and the two layers together enclose a hydrophobic core.Three-stranded helices
Three-stranded beta helices form a distorted triangular prism shape in which each face exhibits parallel inter-strand hydrogen bonding. One of the three sheets that form the repeating structural motif can appear "bent" relative to the other two, which face each other as in the two-stranded helix. Two of the three linking loops between the sheets can be of arbitrary length and can even contain other structural domains; the third is restricted to two resides. A characteristic common hexapeptide repeat found in both left- and right-handed helices is the sequence. Known three-stranded helices are appreciably longer than their two-stranded counterparts.
The first beta-helix was observed in the enzyme pectate lyase, which contains a seven-turn helix that reaches 34 Å (3.4 nm) long. The P22 phage tailspike protein, a component of the P22 bacteriophage, has 13 turns and in its assembled homotrimer is 200 Å (20 nm) in length. Its interior is close-packed with no central pore and contains both hydrophobic residues and charged residues neutralized by salt bridges.
Both pectate lyase and P22 tailspike protein contain right-handed helices; left-handed versions have been observed in enzymes such as UDP-N-acetylglucosamine acyltransferase and archaeal carbonic anhydrase. Other proteins that contain beta helices include the antifreeze proteins from the beetle Tenebrio molitor (right-handed) and from the spruce budworm, Choristoneura fumiferana (left-handed), where regularly spaced threonines on the β-helices bind to the surface of ice crystals and inhibit their growth.
Beta helices can associate with each other effectively, either face-to-face (mating the faces of their triangular prisms) or end-to-end (forming hydrogen bonds). Hence, β-helices can be used as "tags" to induce other proteins to associate, similar to coiled coil segments.
External links
- SCOP family of right-handed β-helices
- SCOP family of left-handed β-helices
- CATH β-helix protein family
References
- Branden C, Tooze J. (1999). Introduction to Protein Structure 2nd ed. Garland Publishing: New York, NY. pp 84-6.
- Dicker IB and Seetharam S. (1992) "What is Known about the Structure and Function of the Eschericia-coli Protein FirA" Mol. Microbiol., 6, 817-823.
- Kisker C, Schindelin H, Alber BE, Ferry JG and Rees DC. (1996) "A left-handed β-helix revealed by the crystal structure of a carbonic anhydrase from the achaeon Methanosarcina thermophile", EMBO J., 15, 2323-2330. (Left-handed)
- Liou YC, Tocilj A, Davies PL and Jia Z. (2000) Mimicry of ice structure by surface hydroxyls and water of a beta-helix antifreeze protein." Nature, 406, 322-324.
- Leinala EK, Davies PL and Jia Z. (2002) "Crystal Structure of β-Helical Anitfreeze Protein Points to a General Ice Binding Model", Structure, 10, 619-627.
- Raetz CRH and Roderick SL. (1995) "A Left-Handed Parallel β Helix in the Structure of UDP-N-Acetylglucosamine Acyltransferase", Science, 270, 997-1000. (Left-handed)
- Steinbacher S, Seckler R, Miller S, Steipe B, Huber R and Reinemer P. (1994) "Crystal structure of P22 tailspike protein: interdigitated subunits in a thermostable trimer", Science, 265, 383-386. (Right-handed)
- Vaara M. (1992) "Eight bacterial proteins, including UDP-N-acetylglucosamine acyltransferase (LpxA) and three other transferases of Escherichia coli, consist of a six-residue periodicity theme", FEMS Microbiol. Lett, 97, 249-254.
- Yoder MD, Keen NT and Jurnak F. (1993) "New domain motif:the structure of pectate lyase C, a secreted plant virulence factor", Science, 260, 1503-1507. (Right-handed)
| Protein secondary structure | ||
|---|---|---|
| Helices: | α-helix | 310 helix | π-helix | β-helix | Polyproline helix | Collagen helix | |
| Extended: | β-strand | Turn | Beta hairpin | Beta bulge | α-strand | |
| Supersecondary: | Coiled coil | Helix-turn-helix | EF hand | |
| Secondary structure propensities of amino acids | ||
| Helix-favoring: | Methionine | Alanine | Leucine | Glutamic acid | Glutamine | Lysine | |
| Extended-favoring: | Threonine | Isoleucine | Valine | Phenylalanine | Tyrosine | Tryptophan | |
| Disorder-favoring: | Glycine | Serine | Proline | Asparagine | Aspartic acid | |
| No preference: | Cysteine | Histidine | Arginine | |
| ←Primary structure | Tertiary structure→ | |
Proteins are large organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid residues.
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β sheet (also β-pleated sheet) is the second form of regular secondary structure in proteins — the first is the alpha helix — consisting of beta strands
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hydrogen bond is a special type of dipole-dipole bond that exists between an electronegative atom and a hydrogen atom bonded to another electronegative atom. This type of bond always involves a hydrogen atom, thus the name.
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Protein-protein interactions refer to the association of protein molecules and the study of these associations from the perspective of biochemistry, signal transduction and networks.
The interactions between proteins are important for many biological functions.
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The interactions between proteins are important for many biological functions.
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ion is an atom or molecule which has lost or gained one or more electrons, making it positively or negatively charged. A negatively charged ion, which has more electrons in its electron shells than it has protons in its nuclei, is known as an anion
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For the plant, see .
Glycine (abbreviated as Gly or G)[1] is the organic compound with the formula HO2CCH2NH2.
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Aspartic acid or aspartate (abbreviated as Asp or D; Asx or B represent either aspartic acid or asparagine)[1] is an α-amino acid with the chemical formula HO2CCH(NH2)CH2CO2H.
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Calcium (IPA: /ˈkalsiəm/) is the chemical element in the periodic table that has the symbol Ca and atomic number 20. It has an atomic mass of 40.078.
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hydrophobicity (from the combining form of water in Attic Greek hydro- and for fear phobos) refers to the physical property of a molecule (known as a hydrophobe) that is repelled from a mass of water [1].
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structural motif is a three-dimensional structural element or fold within the chain, which appears also in a variety of other molecules. In the context of proteins, the term is sometimes used interchangeably with "structural domain," although a domain need not be a motif
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citation, footnoting or external linking.
A structural domain is an element of overall structure within a protein that is self-stabilizing and often folds independently of the rest of the protein chain.
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1 nanometre =
SI units
010−9 m 010−3 μm
US customary / Imperial units
010−9 ft 010−9 in
A nanometre (American spelling: nanometer, symbol nmSI units
010−9 m 010−3 μm
US customary / Imperial units
010−9 ft 010−9 in
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The P22 virus is a bacteriophage, or a virus that infects bacteria - in this case Salmonella. Its circular, double-stranded DNA genome is about 40 kilobases long. Like many phage viruses, it has been used in molecular biology to induce mutations in cultured bacteria and to
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bacteriophage (from 'bacteria' and Greek phagein, 'to eat') is any one of a number of viruses that infect bacteria. The term is commonly used in its shortened form, phage.
Typically, bacteriophages consist of an outer protein hull enclosing genetic material.
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Typically, bacteriophages consist of an outer protein hull enclosing genetic material.
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Trimer might refer to:
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- trimer (chemistry), a reaction product composed of three identical molecules
- trimer (biochemistry), a compound of three macromolecules non-covalently bound
- Trimer, a commune of the Ille-et-Vilaine département, in France
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salt bridge, in chemistry, is a laboratory device used to connect the oxidation and reduction half-cells of a galvanic cell (voltaic cell), a type of electrochemical cell. Salt bridge usually comes in two types: glass tube and filter paper.
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Enzymes are proteins that catalyze (i.e. accelerate) chemical reactions.[1] In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, the products.
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Carbonic anhydrase (carbonate dehydratase) is a family of metalloenzymes (enzymes that contain one or more metal atoms as a functional component of the enzyme) that catalyze the rapid conversion of carbon dioxide to bicarbonate and protons, a reaction that occurs rather
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Antifreeze is used in internal combustion engines, and for many other heat transfer applications, such as electronics cooling and chillers for HVAC. Compounds are added to water to reduce the freezing point of the mixture to below the lowest temperature that the system is likely to
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T. molitor
Binomial name
Tenebrio molitor
Linnaeus, 1758
Mealworms are the larval form of the mealworm beetle, Tenebrio molitor, a species of darkling beetle.
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Binomial name
Tenebrio molitor
Linnaeus, 1758
Mealworms are the larval form of the mealworm beetle, Tenebrio molitor, a species of darkling beetle.
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Threonine (abbreviated as Thr or T)[1] is an α-amino acid with the chemical formula HO2CCH(NH2)CH(OH)CH3. Its codons are ACU and ACA. This essential amino acid is classified as polar.
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ICE may refer to:
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- Internal combustion engine, a fuel engine
- In case of emergency, the emergency contact program created after the 7 July 2005 London Bombings
- International Cometary Explorer, a former spacecraft
- Integrated Collaboration Environment
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coiled coil is a structural motif in proteins, in which 2-7[1] alpha-helices are coiled together like the strands of a rope (Dimers and trimers are the most common types).
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secondary structure is the general three-dimensional form of local segments of biopolymers such as proteins and nucleic acids (DNA/RNA). It does not, however, describe specific atomic positions in three-dimensional space, which are considered to be tertiary structure.
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alpha helix (α-helix) is a right-handed coiled conformation, resembling a spring, in which every backbone N-H group donates a hydrogen bond to the backbone C=O group of the amino acid four residues earlier ( hydrogen bonding). (See also helix.
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310-helix is a type of secondary structure found (rarely) in proteins.
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Structure
The amino acids in a 310-helix are arranged in a right-handed helical structure. Each amino acid corresponds to a 120° turn in the helix (i.e...... Click the link for more information.
pi helix (or π-helix) is a type of secondary structure found (rarely) in proteins.
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Standard structure
The amino acids in a standard π-helix are arranged in a right-handed helical structure. Each amino acid corresponds to a 87° turn in the helix (i.e...... Click the link for more information.
In proteins, a left-handed polyproline II helix (PPII, poly-Pro II) is formed when sequential residues all adopt (φ,ψ) backbone dihedral angles of roughly (-75°, 150°) and have trans isomers of their peptide bonds.
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collagen helix, or type 2 helix, is a major shape in quaternary structure. It consists of a triple helix made of the repetitious amino acid sequence glycine - proline - hydroxyproline.
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β sheet (also β-pleated sheet) is the second form of regular secondary structure in proteins — the first is the alpha helix — consisting of beta strands
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