Protein Structure and Proline Analysis

R-groups in B-strands oriented on the same side of the plane affect the amphipathic nature, leading to distinct hydrophobic and hydrophilic faces.

Amphipathic B-sheets are characterized by having both hydrophobic and hydrophilic faces due to the polarity differences of R-groups.

Adjacent R-groups being oriented in the same direction aids in the formation of a flat structure necessary for B-sheets.

<p>Flat B-sheets are rare because hydrophobic faces are typically buried away from the aqueous environment, minimizing unfavorable interactions.</p> Signup and view all the answers

<p>The zigzag backbone arrangement provides stability and accommodates the orientation of R-groups necessary for the sheet's properties.</p> Signup and view all the answers

<p>Cis and trans proline have lower energy due to their rigidity and special bonding constraints.</p> Signup and view all the answers

<p>The two main secondary structures are alpha-helices and beta-sheets.</p> Signup and view all the answers

<p>Peptide bonds possess a net electric dipole moment due to the partial positive charge on the nitrogen and partial negative charge on the carbonyl oxygen.</p> Signup and view all the answers

<p>Intrachain hydrogen bonds in alpha-helices stabilize the structure by forming between the carbonyl oxygen of one amino acid and the amide hydrogen of another.</p> Signup and view all the answers

<p>Beta-strands align laterally to form beta-sheets, held together by hydrogen bonds between the adjacent strands.</p> Signup and view all the answers

<p>Loops and turns facilitate the transition between different secondary structures and contribute to the overall 3D shape of proteins.</p> Signup and view all the answers

<p>The cis conformer of proline is rarely observed due to the steric hindrance and unfavorable interactions associated with its configuration.</p> Signup and view all the answers

<p>A continuous set of amino acids in an alpha-helix forms hydrogen bonds that maintain a consistent helical structure.</p> Signup and view all the answers

<p>The R-groups affect the cc-helix properties by determining whether the helix is hydrophobic, amphipathic, or hydrophilic, influencing its folding and function.</p> Signup and view all the answers

<p>Glu and Lys contribute to stabilizing the helix through salt bridges, which are interactions that enhance the structural integrity of the helix.</p> Signup and view all the answers

<p>R4's orientation can determine interactions with other molecular components, influencing the helix's functional capabilities.</p> Signup and view all the answers

<p>Having polar and non-polar R-groups on opposite sides allows for optimal interaction with the aqueous environment and contributes to protein stability.</p> Signup and view all the answers

<p>Residues positioned far apart from each other can destabilize the helix, while residues close together can form stabilizing interactions.</p> Signup and view all the answers

<p>The helical wheel arrangement aids in understanding the spatial orientation of residues, influencing helix-turn-helix motif formation.</p> Signup and view all the answers

<p>Hydrophobic amino acids tend to cluster together away from the aqueous environment, dictating the helix's folding pattern and stability.</p> Signup and view all the answers

<p>Interactions between residues are critical because they facilitate the necessary conformational changes that lead to an energetically favorable 3D structure.</p> Signup and view all the answers

<p>Glycine is important because it is achiral, small, and allows for flexibility in the backbone structure of B-strands.</p> Signup and view all the answers

<p>Proline often introduces kinks in the backbone, affecting the tightness and flexibility of B-turns.</p> Signup and view all the answers

<p>Phi angles restrict the conformations of the backbone, influencing the overall structure and stability of peptides.</p> Signup and view all the answers

<p>Hydrogen bonds may occur between specific residues, such as glycine and proline, but are not essential for B-strand stability.</p> Signup and view all the answers

<p>Antiparallel B-strands refer to strands that run in opposite directions, which facilitates optimal hydrogen bonding and stability.</p> Signup and view all the answers

<p>Alternating polar and non-polar residues help to stabilize the B-sheet structure by promoting interactions with the surrounding environment.</p> Signup and view all the answers

<p>Proline's rigid structure can restrict the flexibility of the peptide backbone, limiting conformational diversity.</p> Signup and view all the answers

<p>Glycine's small size and flexibility enable tighter turns and greater compaction in the protein structure.</p> Signup and view all the answers

<p>It allows for close packing of the sheets, contributing to structural stability.</p> Signup and view all the answers

<p>CcKeratin has two coiled helices forming a right-handed supercoil, while Collagen consists of three right-handed helices.</p> Signup and view all the answers

<p>Hydrophobic amino acids at 'a' and 'd' positions in the heptad repeat facilitate stable coiled coil formation.</p> Signup and view all the answers

<p>B-sheets maintain a level of flexibility despite being extended and cannot be stretched like some other structures.</p> Signup and view all the answers

<p>Disulfide bonds provide additional structural support, enhancing its rigidity and toughness.</p> Signup and view all the answers

<p>Increased crosslinking results in greater rigidity and structural integrity due to the enhanced network of collagen molecules.</p> Signup and view all the answers

<p>Fibroin exhibits greater flexibility due to fewer covalent crosslinks compared to the other two proteins.</p> Signup and view all the answers

<p>Variations in amino acids lead to differences in protein structures and functions, resulting in diverse protein families.</p> Signup and view all the answers