Alpha-helical structure

Lyu PC, Liff MI, Marky LA et al (1990) Side-chain contributions to the stability of alpha-helical structure in peptides. Science 250 669-673... 

Usui, K., Takahashi, M., Nokihara, K. and Mihara, H. (2004b). Peptide arrays with designed alpha-helical structures for characterization of proteins from FRET fingerprint patterns. Mol. Divers. 8, 209-218. 

P. V. Hauschka and S. A. Carr, Calcium-dependent alpha-helical structure in osteocalcin, Biochemistry 21, 2538-2547 (1982). 

It can be assumed that the amino acids following this hinge region (Val 93 to Leu 447) are part of the head domain. The point of papain cleavage is at amino acid 82 27. TTie core part of the polypeptide chain is mainly folded in )3-sheets (34 %) and to a lesser extent (15 %) arranged in alpha-helical structures 7. In contrast with CBH I the core of CBH II possesses only 2 disulfide bridges (176-235 368-415) and four free sulfhydryl groups. Similarly to CBH I carboxyl functions are involved in the active center (Asp 175 and Glu 184) 28. 

Vos MD, Ellis CA, Bell A, Birrer MJ, Clark GJ (2000) Ras uses the novel tumor suppressor RASSFl as an effector to mediate apoptosis. J Biol Chem 275 35669-35672 Voss T, Wallner E, Czernilofsky AP, Freissmuth M (1993) Amphipathic alpha-helical structure does not predict the ability of receptor-derived synthetic peptides to interact with guanine nucleotide-binding regulatory proteins. J Biol Chem 268 4637-4642... 

Fig. 1 Structure of the neuronal SNAREs. Upper panel domain structure of the three neuronal SNARE proteins involved in synaptic vesicle fusion. Syntaxin 1A and SNAP-25 (contains two SNARE motifs) are associated with the presynaptic membrane, whereas synaptobrevin 2 is synaptic vesicle associated. The SNARE motifs form a stable complex (core complex) whose crystal structure has been analyzed (lower panel). In the complex, each of the SNARE motifs adopts an alpha-helical structure, and the four alpha-helices are aligned in parallel forming a twisted bundle (modified from Sutton et al. 1998). Stability of the complex is mediated by layers of interaction (—7 to +8) in which amino acids from each of the four alpha-helices participate (see text).

Li-Smerin, Y, Hackos, D. H., and Swartz, K. J. (2000). Alpha-helical structural elements within the voltage-sensing domains of a K+ channel./ Gen. Physiol. 115, 33-50. 

Porins adopt alpha helical structures in transmembrane segments. 

Hi, R., Osada, S., Yumoto, N., and Osumi, T. Characterization of the amino-terminal activation domain of peroxisome proliferator-activated receptor alpha. Importance of alpha-helical structure in the transactivating function. J Biol Chem 274 (1999) 35152-35158. 

The structure of the kinesin monomer is classified into the three subdomains—head, neck-linker, and tail (see Figure I.IA). The head domain (residue 1-323) contains a nucleotide-binding pocket, a catalytic site, which controls the conformational state of the neck-linker (residue 324-338) made of 15 amino acids. The neck-helix domain (residues from 339 to the C-terminus), extended from the neck-linker, forms an alpha-helical structure dimeric kinesins are made via coiled-coil interactions between the neck-helices from two monomers (see Figure I.IA). 

Indicate whether each statement is true or false (a) In the alpha helical structure of proteins, hydrogen bonding occurs between the side chains (R groups), (b) Dispersion forces, not hydrogen bonding, holds beta sheet structures together. 

Ogawa, M. Kanamaru, J. Miyashita, H. Tamiya, T. Tsuchiya, T. Alpha-helical structure of fish actomyosin changes during setting. J. Food Sci. 1995, 60, 297. 

A number of design principles are not specific to magainin-related peptides, but are shared with many peptides, or domains of proteins, which disrupt membrane function. Common features of working models include an abundance of basic amino acids to provide an electrostatic attraction to negatively-charged membranes the adoption of an alpha-helical structure in hydrophobic environments and the assembly of peptide monomers into a multimeric structure that can span a membrane and form a hydrophilic pore (e.g. 13-16),... 

FIGURE 6.10 Cartoon representations of protein structures for (a) bovine catalase (Protein Data Bank [PDB] entry SCAT) and (b) bacteriorhodopsin (PDB entry 3WJK), a proton pump similar to the human visual pigment and found in bacterial cells. In these two examples of protein molecules, we can see the amino acid chain coiled and folded into different structures. Alpha-helical structures are shown in red and beta sheets in yellow. Diagrams such as this are commonly used to depict the complex hierarchical structure of proteins. 

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