Beta structures

In the first edition of this book this chapter was entitled "Antiparallel Beta Structures" but we have had to change this because an entirely unexpected structure, the p helix, was discovered in 1993. The p helix, which is not related to the numerous antiparallel p structures discussed so far, was first seen in the bacterial enzyme pectate lyase, the stmcture of which was determined by the group of Frances Jurnak at the University of California, Riverside. Subsequently several other protein structures have been found to contain p helices, including extracellular bacterial proteinases and the bacteriophage P22 tailspike protein. 

Brack A, Orgel LE (1975) Beta-structures of alternating polypeptides and their possible prebiotic significance. Nature 256 383-387... 

Schweers O, Schonbrann Hanebeck E, Marx A, Mandelkow E. Structural studies of tau protein and Alzheimer paired helical filaments show no evidence for beta-structure. J Biol Chem 1994 269 24290-24297. 

As has been confirmed by XRD, the framework of montmorillonite has been partly destroyed due to the calcination under high temperature. Most diffraction peaks of montmorillonite are faint. After hydrothermal crystallization the characteristic Bragg reflections for zeolite Beta structure at 7.7° and 22.42° 20 are detected in the composite, indicating the presence of the Beta phase. 

Von Bergen, M. etal. Assembly of tau protein into Alzheimer paired helical filaments depends on a local sequence motif [306QIVYK311] forming beta structure. Proc. Natl. Acad. Sci. USA 97 5129-5134, 2000. 

Kajava, A. V., Aebi, U., and Steven, A. C. (2005). The parallel superpleated beta-structure as a model for amyloid fibrils of human amylin. /. Mol. Biol. 348, 247-252. 

Lotz, B., Brack, A., and Spach, G. (1974). Beta structure of periodic copolypeptides of L-alanine and glycine. Their relevance to the structure of silks./. Mol. Biol. 87, 193-203. 

DeMarco, M. L., and Daggett, V. (2004). From conversion to aggregation Protofibril formation of the prion protein. Proc. Natl. Acad. Sci. USA 101, 2293-2298. Diaz-Avalos, R., Long, C., Fontano, E., Balbirnie, M., Grothe, R., Eisenberg, D., and Caspar, D. L. D. (2003). Cross-beta structure of an amyloid-forming peptide studied by electron nano-crystallography. Fibre Diffract. Rev. 11, 79-86. 

Papanikolopoulou, K., Schoehn, G., Forge, V., Forsyth, V. T., Riekel, C., Hernandez, J.-F., Ruigrok, R. W. H., and Mitraki, A. (2005). Amyloid fibril formation from sequences of a natural beta-structured fibrous protein, the adenovirus fiber. / Biol. Chem. 280, 2481-2490. 

Sass, H. J., Btlldt, G., Beckmann, E., Zemlin, F., Van Heel, M., Zeitler, E., Rosenbusch, J. P., Dorset, D. L., and Massalski, A. (1989). Densely packed beta-structure at the protein-lipid interface of porin is revealed by high-resolution cryo-electron microscopy. J. Mol. Biol. 209,171-1... 

Barghorn, S., Davies, P., Mandelkow, E. (2004) Tau paired hehcal filaments from Alzheimer s disease brain and assembled in vitro are based on beta-structure in the core domain. Biochemistry, 43, 1694-1703. 

Fig. 7. The crystal structure of the C-domain of hemopexin (PDB accession number IHXN) 128) showed a four-bladed p-propeller structure, which because of sequence similarity was also expected in the N-domain. The high degree of beta structure and limited a-helix content agrees with the earlier FTIR analysis.

Fig. 4. Protein sequences of Rhodnius NPl-4 obtained from the gene sequences (45) and confirmed for NPl, NP2, and NP4 by X-ray ciystallography. Identical residues are marked. Alpha and beta structural features are also marked, as is the A-B loop that becomes ordered upon binding of NO (see Section III).

There is a wide variety of so-called globular proteins. Many of these have alpha and beta structures imbedded within the overall globular structure. Beta sheets are often twisted or wrapped into a barrel-like structure. They contain portions that are beta sheet structures... 

Zeolite Beta Structure, Activity, and Selectivity for Catalytic Cracking... 

Proteins occur as helices (alpha structures) and pleated sheets (beta structures). The alpha structures are dependent on intramolecular hydrogen bonds, whereas the beta structures are dependent on intermolecular hydrogen bonding. 

The secondary structure of the plasminogen molecule, as determined by circular dichroism spectra, is 80% random coil, 20% beta-structure, and 0% alpha-helix. Electron microscopy has demonstrated the tertiary structure of plasminogen to be a 22- to 24-nm long spiral filament with a diameter of 2.2 to 2.4 nm. 

The P structure is one of the most important secondary structures in proteins. It occurs in about 80% of the soluble globular proteins whose structures have been determined. In many cases almost the entire protein is made up of P structure. Single strands of extended polypeptide chain are sometimes present within globular proteins but more often a chain folds back on itself to form a hairpin loop. A second fold may be added to form an antiparallel "P meander"102 and additional folds to form P sheets. Beta structures are found in silk fibers (Box 2-B) as well as in soluble proteins. 

Beta structures are found in many small peptides. Tire hormone oxytocin (Fig. 2-4), the antibiotics gramicidin S (Fig. 2-4) and valinomycin (Fig. 8-22), and the mushroom peptide antamanide (Box 28-B) are among these. The cyclic structures of these compounds favor formation of antiparallel (3 strands with sharp turns at the ends. Polypeptide antibiotics that have alternating... 

Fig. 4 Pepplot graphic of secondary structure predictions of the mating pheromones Er-1 (a), Er-2 (b), and Er-10 (c). Dotted lines are used to distinguish the curves for alpha structures from the curves for beta structures. The horizontal dotted and solid lines indicate the minimum levels for predicting beta and alpha structures. The data for Er-1 are taken from ref. 13 and Er-10 from ref. 15 by permission of the American Society of Biochemistry and Molecular Biology and the American Chemical Society, respectively.

Munger, J. S., Harpel, J. G., Gleizes, P. E., Mazzieri, R., Nunes, I., and Rifkin, D. B. (1997). Latent transforming growth factor-beta structural features and mechanisms of activation. Kidney Int. 51, 1376-1382. 

Ono, S., Lee, S., Mihara, R, Aoyagi, R, Kato, T., and Yamasaki, N. (1990). Biochim. Biophys. Act. 1022, 237-244. Design and synthesis of basic peptides having amphipathic beta structure and their interaction with phospholipid membranes. 

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