The E2A gene encodes two alternatively spliced products, E12 and E47. The two proteins differ in their basic helix-loop-helix motifs (bHLH), responsible for DNA binding and dimerization. Although both E12 and E47 can bind to DNA as heterodimers with tissue-specific bHLH proteins, E12 binds to DNA poorly as homodimers. An inhibitory domain in E12 has previously been found to prevent E12 homodimers from binding to DNA. By measuring the dissociation rates using filter binding and electrophoretic mobility shift assays, we have shown here that the inhibitory domain interferes with DNA binding by destabilizing the DNA-protein complexes. Furthermore, we have demonstrated that substitution of basic amino acids (not other amino acids) in the DNA-binding domain of E12 can increase the intrinsic DNA-binding activity of E12 and stabilize the binding complexes, thus alleviating the repression from the inhibitory domain. *This ability of basic amino acids to stabilize DNA-binding complexes may be of biological significance in the case of myogenic bHLH proteins, which all possess two more basic amino acids in their DNA binding domain than E12.* To function as heterodimers with E12, the myogenic bHLH proteins may need stronger DNA binding domains. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=145871 Helix-capping interactions were found to contribute to helix stability, even when the substitution site was not at the end of the peptide- the H-bonds. BETA TURN. Many antiparallel beta sheets are formed by a single peptide chain continually looping back on itself. The loop between the two hydrogen-bonded segments, known as a beta turn, consistently contains one to three (usually two) amino acids. The amino acids in a beta turn do not form hydrogen bonds, but other interactions may stabilize their positions. A further consistency is that, from a perspective where the side chain of the final hydrogen-bonded amino acid projects outward toward the viewer, the turn is always to the right. http://science.jrank.org/pages/5539/Proteins.html -that is a good website
False. A peptide bond joins the carboxyl group of one amino acid to the amino group of another amino acid.
Yes, glycine is an amino acid.
The pitch of a helix is defined as the distance along the helical axis that results in one full turn of the helix. In the case of amino acid helices, this value is an average value of about 5.5 Angstroms. A-DNA B-DNA Z-DNA Right-handed helix Right-handed Left-handed Short and broad Long and thin Longer and thinner Helix Diameter 25.5A 23.7A 18.4A Rise / base-pair 2.3A 3.4A 3.8A Base-pair / helical turn ~ 11 ~ 10 ~ 12 Helix pitch 25A 34A 47A Tilt of the bases 20 deg -1 deg -9 deg Also see http://tigger.uic.edu/classes/phys/phys461/phys450/ANJUM04/
Yes, tyrosine is a polar amino acid.
The amino acid code for tryptophan is "Trp."
The amino acid side chain residues in an helix orient themselves outward from the center of the helix.
3.6 amino acid.
Hydrogen bonding is the primary interaction that stabilizes the alpha helix and beta pleated sheets of a protein. In the case of alpha helices, hydrogen bonds form between the carbonyl oxygen of one amino acid residue and the amide hydrogen of another residue in the chain. In beta sheets, hydrogen bonds form between adjacent strands of the sheet.
Hydrogen bonds between the carbonyl oxygen of one amino acid and the amine hydrogen of an amino acid that is four residues down the sequence stabilize the formation of an alpha-helix in a protein. This creates a helical backbone structure that provides stability to the protein's secondary structure.
When non polar residues are situated near the helix termini, they are often exposed to solvent. Proteins will compensate for this problem by helix capping. This is simply the provision of H-bond partners for the otherwise bare N-H and C=O groups. Folding places the hydrophobic regions inside the protein.
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Alpha helices themselves are not classified as non-polar; rather, they can contain both polar and non-polar amino acids. The properties of an alpha helix depend on the specific sequence of amino acids it contains. Non-polar side chains may contribute to the stability of the helix by participating in hydrophobic interactions, while polar side chains can interact with the surrounding environment. Thus, the overall character of an alpha helix is determined by its amino acid composition.
proline is not an amino acid it is an imino acid
Codons are sequences of three nucleotides that connect the double stranded helix of DNA which are described as "ladder rungs" and they each call for a specific amino acid.
Anthranilic acid is not an amino acid because it lacks an amino group (-NH2) within its molecular structure, which is a defining feature of amino acids. Despite its name containing "acid," anthranilic acid is actually a precursor to various amino acids but is not classified as an amino acid itself.
False. A peptide bond joins the carboxyl group of one amino acid to the amino group of another amino acid.
there is amino acid in your stomach.