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Topic: Pleated

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3.2 Sheets Beta sheets are found in two forms designated as "Antiparallel" or "Parallel" based on the relative directions of two interacting beta strands. The basic unit of a beta sheet is a beta strand (which can be thought of as a helix with n = 2 residues/turn) with approximate backbone dihedral angles phi = -120 and psi = +120 producing a translation of 3.2 to 3.4 Angstroms/residue for residues in antiparallel and parallel strands, respectively. The extended conformation of the polypeptide strands composing a beta sheet was already proposed in the 1930's from diffraction data ( 1.0) but researchers had to wait until the X-ray crystal structure of lysozyme was solved before getting a look at one in a globular protein. www.cryst.bbk.ac.uk /PPS2/course/section8/ss-960531_10.html

Botany online: Macromolecules - Peptides and Proteins Anti-parallel and parallel beta -pleated-sheets (arrows) in plastocyanin. Anti-parallel beta -pleated-sheet: In this configuration, the polypeptide chains arrange in an antiparallel manner. Chymotrypsin, a parallel beta -sheet (upper part of the picture), anti-parallel beta -sheet (at the bottom of the picture), alpha -helix (in the background). www.biologie.uni-hamburg.de /b-online/e17/17d.htm

Right.html Beta pleated sheets are extended regions of proteins that are stabilized by contact through hydrogen bonds with similar regions in a different part of the peptide chain. Beta pleated sheets and alpha helices are said to make up the secondary structure of polypeptide chains. These regularities tend to be of two kinds: alpha helices and beta pleated sheets. mbclserver.rutgers.edu /~sofer/genetics/Proteins/RightSource7.html

BB 350 Oregon State University Beta pleated sheets are arrangements of beta pleated strands that are are arranged parallel or anti-parallel to each other. Differences between alpha helices and beta pleated strands - carbonyl and amides are arranged parallel to the axis of an alpha helix, but perpendicular to the axis of beta pleated strands. They contain relatively short regions of secondary structure, such as alpha helices or beta sheets, but the short regions are interrupted by turns, links, etc. The overall 'shape' of a globular protein is therefore a function of the way in which the secondary structures are linked together. oregonstate.edu /instruction/bb350/highlightsprotstruct.html

Proteins 6 Fibroin, the protein of silk, is characterized by a beta-pleated-sheet structure, and the core of many globular proteins consists of beta sheets. Pleated sheets can also form between different regions of the same polypeptide chain. The regularity is due to interactions between the atoms of the uniform backbone of the polypeptide chain. www.bergen.org /AAST/projects/gel/proteins6.htm

RNases The tertiary structure of a polypeptide chain is the next level of conformation or shape adopted by the alpha-helices or beta-pleated sheets of the chain. Beta sheets occur in variable amounts in the polypeptide chains of globular proteins e.g. Substantially different from the alpha-helix in that it's a sheet rather than a rod and polypeptide chain is fully stretched rather than tightly coiled as in helix. www.cs.stedwards.edu /chem/Chemistry/CHEM43/CHEM43/RNases/Structure/STRUCTURE.HTML

Protein Structure 4 The common secondary structures are alpha helices [ 44 ], beta strands and beta sheets [ 44 ], turns and random coil [ 19 ]. Beta turns are subdivided into numerous types on the basis of the details of their geometry. There are also mixed [ 27 ] beta sheets, in which some pairs of strands run parallel and some anti-parallel. www-mitchell.ch.cam.ac.uk /courses/pro4.html

Hayden MR, et al. Type 2 Diabetes Mellitus as a Conformational Disease. JOP. J Pancreas (Online) 2005; 6(4):287-302. [Full text] Beta cell mass (both number and volume of cells) is reduced in the later phases of T2DM as a result of apoptosis, especially in rapidly replicating beta cells [ 33 ]. The beta cell is poorly equipped to handle redox stress as compared to other cells such as hepatocytes [ 76, 83 ], and this very sensitivity has allowed researchers to use the oxidizing agents streptozotocin and alloxan to create diabetic animal models. Thus, transcription in beta cells is not regulated by insulin itself but by translational and post-translational events that are themselves regulated by extracellular glucose levels [ 29, 30, 31 ]. www.joplink.net /prev/200507/02.html

Conformation - InformationBlast Tertiary conformation is the twisting of alpha helices and beta pleated sheets into larger structures, due to the formation of disulfide bridges, a weak form of chemical bond. Secondary conformation is the twisting of polypeptides to form alpha helices, beta sheets, and other shapes. Primary conformation is the sequence of amino acids that are joined to form the protein's polypeptide chain(s). www.informationblast.com /Conformation.html

Dr Chromo's School: the beta-pleated sheet The beta - pleated sheet is a secondary structure found in proteins in which hydrogen bonds are formed between two parts of the protein chain that can be far apart. In yellow, the parts of the protein involved in the beta - pleated sheets, in pink, some alpha - helices. Diagrams 2 and 3 show two different views of the same beta - pleated sheets rich protein. www.rothamsted.bbsrc.ac.uk /notebook/courses/guide/protalbeta.htm

P1F9Desc.html Alpha helices are shown as purple coloured helices and beta pleated sheets as yellow stretches of ribbon. The roughly oval shaped structure is dominated by a lattice of beta pleated sheets running diagonally across the molecule. www.aber.ac.uk /~mpgwww/Lipid/P1F9Desc.html

AMINO ACIDS AND PROTEINS - Secondary structure The secondary structure of proteins involves chains of amino acids forming structures such as alpha helices and beta pleated sheets. One example of a beta sheet in a small globular protein is at the Center for Advanced Biotechnology and Medicine page. Beta sheets form when two or more polypeptide chains line up side by side. www.sheffcol.ac.uk /projects/access_online/Health_Science_Access/Biochemistry/Proteins/secondary.htm

Dr Chromo's school: protein structure and diversity Beta - pleated sheets: the amino acids adopt the conformation of a sheet of paper and the structure is stabilized by hydrogen bonds between amino acids in different polypeptide strands. The tertiary structure (or conformation) is the way random coils, alpha -helixes and beta -pleated sheets fold in respect to each other, ie it refers to the protein as a whole. The peptide is coiled around an imaginary cylinder and stabilized by hydrogen bonds formed between components of the peptide bonds. www.rothamsted.bbsrc.ac.uk /notebook/courses/guide/prot.htm

Botany online: Macromolecules - Lectins The polypeptide chain of ConA is composed of 237 Amino acid residues; its tertiary structure has an exceptionally high proportion of beta - pleated sheets, the active molecule is a tetramer. The alpha -chain is homologous to section 70-119 of ConA, the beta -chain to sections 120-237 and 1-69. This led to the assumption that it were not only the carbohydrate parts that were important for the binding but that certain, non-specific protein-protein interactions (weak interactions) were stabilizing the complex. www.biologie.uni-hamburg.de /b-online/e17/17h.htm

The X-ray crystal structure of the transcription factor IIA (TFIIA) in complex with the TATA-box-binding protein (TBP) and TAT For four of the five structures a pleated sheet and turns (NAEY and PKR) and a bend and a extended beta sheet were aligned (AVIMRIRE). It aligned the helix (LKTV) for all five structures.The two amino acids before that stretch are conserved: Lor V followed by D or E. The sequences also align for the pleated sheet (NAEY) with the Y occuring in four of the sequences (F in the fifth). EE EE EEEEE SS The structure alignment aligned the extended pleated sheet (VATV), the helix (LKTV) for all five structures. www.bioinformaticscourses.com /ISB/sp2002/1YTF

Intermediate PrP to explain the entropy of the prion molecule pleated sheet conformation can be achieved in vitro, e.g. spontaneous conversion of a prions econdary structure to a beta-pleated sheet, supposes a found to comprise mainly beta - pleated sheets. bse.airtime.co.uk /intermediate.html

The Rothberg Institute: Community TSC: Visualization The highest level of organization in a protein is referred to as its tertiary structure and refers to the arrangement of various secondary structural elements such as alpha helices, beta pleated sheets and beta turns. This long string forms several different types of secondary structures such as alpha helices (springs), beta pleated sheets and beta turns. The ribbon model of a protein shows the three dimensional arrangement secondary structural elements and is a flat ribbon like representation of the backbone of the string of amino acid residues. www.childhooddiseases.org /visualization.html

2000-Unit1Objectives.doc Secondary: The spatial relationships between amino acids which are close to one another in the chain; the entire key to secondary structure is maximizing hydrogen bonds; we are after optimal hydrogen bonding; pleated sheet and alpha helix structures permit optimal hydrogen bonding. Gly and Pro residues often occur in beta turns, the former because it is small and flexible and the second because peptide bonds involving the imino nitrogen of proline readily assume the cis configuration. The sheets can be either anti-parallel, in which the amino-terminal to carboxyl-terminal orientation of adjacent chains in inverse, or parallel. umed.med.utah.edu /ms1/biochem/study/2000-Unit1Objectives.doc

Introduction to protein structure In contrast to alpha helices, b eta pleated sheets are extended polypeptide chains, called "strands", (i.e., they are not tightly coiled) that form "sheets" by virtue of hydrogen bonding between NH and CO groups of different chains. The beta -turn is typified by hydrogen bonding of the n amino acid CO group with the n+3 residue NH group. The alpha helix is a tightly coiled, rod-like arrangement with the "backbone" comprised of the a carbon, carbonyl group, and amino group with the side chains (R groups) radiating outward. neurobio.mcphu.edu /GalloWeb/Loudonintroduction_to_protein_structur.htm

List of Classification Articles Sternberg, M.J.E. and Thornton, J.M. (1977) On the conformation of proteins: an analysis of beta-pleated sheets. Chothia, C. and Janin, J. Relative orientation of close-packed beta-pleated sheets in proteins. Lesk, A.M., Brändén, C.-I. and Chothia, C. Structural principles of alpha/beta barrel proteins: the packing of the interior of the sheet. bioinformatics.uams.edu /scop/refs.html

don-a-z.sgm Treatment of the entire sheet (internal treatment) entails mixing the additives with the paper pulp, in which case they are known as wet-end additives. The sheets are either fed by operators to the carrier saddle at various stations, or are fed automatically. Barrier sheets are frequently made of an inferior quality of paper, one which will eventually develop acidity that can in turn be transferred to the facing text leaves, weakening them. palimpsest.stanford.edu /don/don-a-z.sgm

Description of transplant,anus,torpor,urology,generalize,pulmo-,melanocyte,beta pleated sheet,dependent diabetes,fertilized Word Descriptions transplant, anus, torpor, urology, generalize, pulmo-, melanocyte, beta pleated sheet, dependent diabetes, fertilized Determinations of the words transplant, anus, torpor, urology, generalize, pulmo-, melanocyte, beta pleated sheet, dependent diabetes, fertilized Meaning of transplant, anus, torpor, urology, generalize, pulmo-, melanocyte, beta pleated sheet, dependent diabetes, fertilized www.english-test.net /mcat/vocabulary/words/068/mcat-descriptions.php

chapter5.doc beta pleated sheets secondary protein structure which is a sheet of antiparallel chains folded into accordion pleats. The major types of secondary structure are alpha helix and beta pleated sheets. Structural Polysaccharides: Cellulose: Linear unbranched polymer of D-glucose in beta 1-4 linkages. www.geneinfo.net /downloads/bio101/chapter5.doc

Botany online: Macromolecules - Anti-parallel beta-pleated-sheet Configuration of a polypeptide chain that is part of a sheet. nsdl.lon-capa.org /res/msu/botonl/b_online/e17/antipara.htm

Amyloidoses and Prion Diseases A-beta peptide is actually a mixture of peptides with uniform amino-terminus and variable length, 40-43 residues. The model suggests that amyloid fibrils are stabilized by interstrand backbone H-bonding, as in all beta sheets, and intersheet hydrophobic and van der Waals packing interactions. The transthyretin structure may be predisposed to amyloidosis by its largely beta sheet structure. www.tulane.edu /~biochem/med/prion.htm

Homepage ABC/Schlaad Driven by hydrogen bridging interactions between adjacent acetoacetoxy groups and compensation of dipole moments, PAEMA chains should first self-assemble into anti-parallel beta-pleated sheets or ribbons of ~12 nm width and then coil up into the helical superstructure. Both the diameter and pitch of the superhelices are about 12 nm and their length is in the order of 200-500 nm, depending on the molecular weight of the building PAEMA chain. www.mpikg-golm.mpg.de /kc/schlaad

Got Essays? - 100% Free Essays, Need I Say More? Alpha helices and beta pleated sheets are joined by less clear structures often grouped together under the name of coil. These are called beta strands and the sheets are called beta-pleated sheets. A protein may contain either or both alpha helices and beta pleated sheets. www.gotessays.com /essays/1128

Learning Objectives for Protein Section Parallel sheets have hydrophobic sides and surfaces covered by main chain strands (often having a helices packed on one side); amino-terminals are located on one side of the sheet carboxyl-terminals the other. Anti-parallel sheets have a hydrophilic side and a hydrophobic side; amino-terminals and carboxyl-terminals are located adjacent to each other on each side of the sheet. Polypeptide chains that associate by hydrogen bonding to form a sheet-like structure that is almost fully extende d; hydrogen-bonding between different strands. umed.med.utah.edu /MS1/biochem/study/learn_ob_protein2003.htm

Protein machines A beta-pleated sheet occurs when the hydrogen bonds are formed between neighboring polypeptide chains either in a parallel or anti-parallel fashion. Proteins fold rapidly into a structure where almost all of the secondary structure is complete - a rough approximation and alignment of the ß-pleated sheets and a-helices. These units fold independently and have beta-pleated sheets with exposed polypeptide chains for binding to other molecules. campus.murraystate.edu /academic/faculty/David.Canning/WEBFILES/321prot.html

jcbtert.htm The pink regions are alpha helices and the orange regions are beta pleated sheets. The arrows drawn to represent the beta pleated sheets tell us whether the beta pleated sheet is parallel or anti-parallel to its neighbour. View My Protean Predicted Structure Plots There are many alpha and beta regions, some of which are comparatively long, and a smaller number of turn and coil regions, which are in general shorter. www.dur.ac.uk /j.c.bolesworth/jcbtert.htm

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