China
Africa
Explore chapters and articles related to this topic
Protein-based Wood Adhesives Current Trends of Preparation and Application
Published in Zhongqi He, Bio-based Wood Adhesives, 2017
Birendra B. Adhikari, Pooran Appadu, Michael Chae, David C. Bressler
The secondary structure of proteins refers to localized structures adopted by a given stretch of amino acid residues. The two most common conformations that make up the secondary structure of proteins are the alpha helix and the beta sheet (Fig. 2). An alpha helix occurs through a regular pattern resulting from formation of several hydrogen bonds between certain amino acid residues in a localized region of a polypeptide chain. Specifically, regular hydrogen bonds between a C=O group of an amino acid residue and an NH group of the amino acid residue located four residues away in a polypeptide chain result in folding of the polypeptide chain in a helical shape (Fig. 2).
Naturally Occurring Polymers—Animals
Published in Charles E. Carraher, Carraher's Polymer Chemistry, 2017
Helices can be described by the number of amino acid residues in a complete “turn.” To fit into a “good” helix, the amino acids must have the same configuration. For proteins, that configuration is described as an l-configuration, with the helix being a “right-handed” helix. This right-handed helix is referred to as an alpha-helix.
Effect of glutamic acid elimination/substitution on the biological activities of S3 cationic amphiphilic peptides
Published in Preparative Biochemistry & Biotechnology, 2020
Mina Sepahi, Reza Ahangari Cohan, Shahin Hadadian, Dariush Norouzian
Secondary structures of peptides were determined by CD far UV, and different secondary structures were observed in absence and presence of LPS. This phenomenon has been reported for many CAPs, most of CAPs have been found to have random coil structure in a buffer solution and alpha helix[12,43] or beta-sheet[12] structures at hydrophobic environments. All S3, S3E3A, and S3E3 had a large portion of random coil structure in absence of LPS. Previously, Tan et al.[12] reported 100% random coil for S3 peptide. Results obtained from CDNN software analysis showed that, in presence of LPS, alpha helix structures were conformed, and a moderate increase was observed in beta-sheet composition for all the peptides.
Amphiphilic peptide binding on crystalline vs. amorphous silica from molecular dynamics simulations
Published in Molecular Physics, 2019
Janani Sampath, Jim Pfaendtner
The LKα14 sequence is LKKLLKLLKKLLKL and is capped with an acetyl group and carboxyl amide group on the N-terminus and C-terminus respectively, to avoid terminal charges. The peptide was generated as an alpha helix using the Molefacture plugin in Visual Molecular Dynamics (VMD) [32]. Past work of LKα14 has shown that the peptide strictly adopts a helical conformation at both hydrophobic and hydrophilic interfaces [26,29,30], and this supported our choice of initialising the peptide as a helix to expedite sampling of preferred states. Below, we show that the peptide undergoes many folding – unfolding and binding – unbinding events, thereby exhaustively sampling configuration space, in spite of the initial ordered conformation. The CHARMM36 force field was used to model the peptide [33].
Characterization of marine bacterial carbonic anhydrase and their CO2 sequestration abilities based on a soil microcosm
Published in Preparative Biochemistry & Biotechnology, 2019
Panchami Jaya, Vinod Kumar Nathan, Parvathi Ammini
The CA of B. safensis isolate AS-75 was α-helix rich based on the secondary structure prediction. They are the first component formed during protein folding and is the most stable element.[50,51] The CA secondary protein structure prediction result showed that the protein has 49.22% alpha helix, 16.06% extended strand, 9.33% beta-turn and 25.33% random coil (Fig. 4a). Although β-CAs were found to be essential for microbial growth of Escherichia coli,[55]Helicobacter pylori,[56] and C. glutamicum,[57] their full physiological role in the biosphere still remains unclear.[58] Certain CA enzymes have a compact structure with a β-sheet core with 5 anti-parallel strands, 4 or more α-helices and a shallow. They can function in the dimers or larger multi-oligomeric states.[5]