Beta-sheet

Figure 2.5 Schematic illustrations of antiparallel (3 sheets. Beta sheets are the second major element of secondary structure in proteins. The (3 strands are either all antiparallel as in this figure or all parallel or mixed as illustrated in following figures, (a) The extended conformation of a (3 strand. Side chains are shown as purple circles. The orientation of the (3 strand is at right angles to those of (b) and (c). A p strand is schematically illustrated as an arrow, from N to C terminus, (bj Schematic illustration of the hydrogen bond pattern in an antiparallel p sheet. Main-chain NH and O atoms within a p sheet are hydrogen bonded to each other.

Figure 2.11 Beta sheets are usuaiiy represented simply by arrows in topology diagrams that show both the direction of each (3 strand and the way the strands are connected to each other along the polypeptide chain. Such topology diagrams are here compared with more elaborate schematic diagrams for different types of (3 sheets, (a) Four strands. Antiparallel (3 sheet in one domain of the enzyme aspartate transcarbamoylase. The structure of this enzyme has been determined to 2.8 A resolution in the laboratory of William Lipscomb, Harvard University, (b) Five strands. Parallel (3 sheet in the redox protein flavodoxin, the structure of which has been determined to 1.8 A resolution in the laboratory of Martha Ludwig, University of Michigan, (c) Eight strands. Antiparallel barrel in the electron carrier plastocyanln. This Is a closed barrel where the sheet is folded such that (3 strands 2 and 8 are adjacent. The structure has been determined to 1.6 A resolution in the laboratory of Hans Freeman in Sydney, Australia. (Adapted from J. Richardson.)...

The interiors of protein molecules contain mainly hydrophobic side chains. The main chain in the interior is arranged in secondary structures to neutralize its polar atoms through hydrogen bonds. There are two main types of secondary structure, a helices and p sheets. Beta sheets can have their strands parallel, antiparallel, or mixed. 

Fig. 4.1.13 A ribbon representation of the crystal structure of recombinant acquorin molecule showing the secondary structure elements in the protein. Alpha-helices are denoted in cyan, beta-sheet in yellow, loops in magenta coelenterazine (yellow) and the side chain of tyrosine 184 are shown as stick representations. From Head et al., 2000, with permission from Macmillan Publishers.

Alzheimer s Disease. Figure 1 A(3 monomers can self-associate to form dimers, trimers and higher oligomers. Globular structures of synthetic A(342 are known as A(3-derived diffusible ligands (ADDLs) (3-12-mers of A(3). These structures are similar to the smallest protofibrils and represent the earliest macromolecular assembly of synthetic A(3. The characteristic amyloid fiber exhibits a high beta-sheet content and is derived in vitro by a nucleation-dependent self-association and an associated conformational transition from random to beta-sheet conformation of the A(3 molecule. Intermediate protofibrils in turn self-associate to form mature fibers. 

Detailed protein structures have been reported for BPI and CETP. Given the aforementioned similarities within this gene family, these protein structures serve as a likely model for the protein structure of PLTP. CETP and BPI are elongated molecules, shaped like a boomerang. There are two domains with similar folds, and a central beta-sheet domain between these two domains. The molecules contain two lipid-binding sites, one in each domain near the interface of the barrels and the central beta-sheet. 

Lazo ND, Meine JG, Downing DT (1995) Lipids are covalently attached to rigid corneocyte protein envelope existing predominantly as beta-sheets a solid state nuclear magnetic resonance study. J Invest Dermatol 105 296-300... 

Hwang JY, Deming TJ (2001) Methylated mono- and di(ethylene glycol)-functionalized beta-sheet forming polypeptides. Biomacromolecules 2 17-21... 

Fig. 19 Lateral model for assembly of peptide mixtures producing laminated P-sheets. Residues in solid circles are on the upper face, residues in dashed circles are on the lower face of the P-sheeL Reproduced from Takahashi et al. [57] with permission. Copyright Wiley-VCH. Numbers refer to the peptide entries in Fig. 18. Arrows are directions of the (antiparallel) beta sheet strands beginning and end of arrow correspond to N- and C-peptide termini respectively...

Resilin-like polypeptide and sequence motif Technique Helices (%) Strands (%) Turns (%) Unordered (%) (or random coil) Beta sheet (%) PPII (%)... 

Lamm MS, Sharma N, Rajagopal K et al (2008) Laterally spaced linear nanoparticle arrays templated by laminated beta-sheet fibrils. Adv Mater 20 447M 51... 

Aggeli A, Bell M, Boden N et al (1997) Engineering of peptide beta-sheet nanotapes. J Mater Chem 7 1135-1145... 

Yang JJ, Pitkeathly M, Radford SE (1994) Far-uv circular-dichroism reveals a conformational switch in a peptide fragment Irom the beta-sheet of hen lysozyme. Biochemistry 33 7345-7353... 

Smith AM, Williams RJ, Tang C et al (2008) Fmoc-diphenylalanine self assembles to a hydrogel via a novel architecture based on pi-pi interlocked beta-sheets. Adv Mater 20 37-41... 

Lamm MS, Rajagopal K, Schneider JP et al (2005) Laminated morphology of nontwisting beta-sheet fibrils constructed via peptide self-assembly. J Am Chem Soc 127 16692-16700... 

Meegan JE, Aggeli A, Boden N et al (2004) Designed self-assembled beta-sheet peptide fibrils as templates for silica nanotubes. Adv Fund Mater 14 31-37... 

Irback A, Sjunnesson F. Folding thermodynamics of three beta-sheet peptides a model study. Proteins 2004 56 110-6. 

Caughey B, Raymond GJ, Bessen RA. Strain-dependent differences in beta-sheet conformations of abnormal prion protein. J Biol Chem 1998 273 32230-32235. 

Kowalewski T, Holtzman DM. In situ atomic force microscopy study of Alzheimer s beta-amyloid peptide on different substrates new insights into mechanism of beta-sheet formation. Proc Natl Acad USA 1999 96 3688-3693. 

Li L, Darden TA, Bartolotti L, Kominos D, Pederson LG. An atomic model for the pleated beta-sheet structure of Abeta amyloid protofilaments. Biophys J 1999 76 2871-2878. 

Poduslo JF, Curran GL, Kumar A, Frangione B, Soto C. Beta-sheet breaker peptide inhibitor of Alzheimer s amyloidogenesis with increased blood-brain barrier permeability and resistance to proteolytic degradation in plasma. J Neurobiol 1999 39 371-382. 

Colombo, G., Roccatano, D., and Mark, A. E. (2002). Folding and stability of the three-stranded beta-sheet peptide betanova Insights from molecular dynamics simulations. Proteins Strud. Fund. Genet. 46, 380—392. 

Wu C, Biancalana M, Koide S, Shea JE (2009) Binding modes of thioflavin-T to the singlelayer beta-sheet of the peptide self-assembly mimics. J Mol Biol 394(4) 627-633... 

Salgado J, Grage SL, Kondejewski LH, Hodges RS, McElhaney RN, Ulrich AS (2001) Membrane-bound structure and alignment of the antimicrobial beta-sheet peptide gramicidin S derived from angular and distance constraints by solid state F-19-NMR. J Biomol NMR 21 191-208... 

Blazyk J, Wiegand R, Klein J, Hammer J, Epand RM, Epand RF, Maloy WL, Kari UP (2001) A novel linear amphipathic beta-sheet cationic antimicrobial peptide with enhanced selectivity for bacterial lipids. J Biol Chem 276 27899-27906... 

Benzinger, T. L., Gregory, D. M., Burkoth, T. S., Miller-Auer, H., Lynn, D. G., Botto, R. E., and Meredith, S. C. (1998). Propagating structure of Alzheimer s beta-amyloid (10-35) is parallel beta-sheet with residues in exact register. Proc. Natl. Acad. Sci. USA 95, 13407-13412. 

Blake, C., and Serpell, L. (1996). Synchrotron X-ray studies suggest that the core of the transthyretin amyloid fibril is a continuous beta-sheet helix. Structure 4, 989-998. 

---