Question

Protein Structure A protein contains a string of amino acids (usually more than 50) that has a biological function. 15ecause proteins are so large, their structure has several levels, all of which are important for the proper functioning of the protein. Ultimately, the sequence of amino acids (ordering of polar and nonpolar amino acids) dictates the 3-dimensional shape of a protein and this dictates its primary function. Level 1: Primary (1") The amino acid sequence of a polypeptide Protein Backbone the sequence of the connected amino acids, notice the location of the R- groups which appear as pendants extending from the protein backbone "necklace." *HN- CH-C N- CH-CNCH-CN- N =CH-C =0" CH2 CH2 c= 0 SH CH-CH NH CHE Gly Ala Asn Cys Leu Figure 1. A pentapeptide showing the protein backbone (a continuous chain of nitrogen-carbonyl-alpha carbon-nitrogen-carbonyl-alpha carbon etc.); this peptide can be represented in abbreviations as Gly-Ala- Asn-Cys-Leu and/or GANCL. Questions 9. Draw a circle around or use a highlighting pen to trace the backbone of the pentapeptide in Figure 1. 10. One end of the string of amino acids is called the amino or N terminus and the other end is called the carboxy or C-terminus. Indicate those on Figure 1.

Answer 1

- Each segment of a protein is the residue of an amino acid. Stroro peptide bonds join the segments, forming the backbone. each other are connected to - Amino acids forming peptides. > Peptides are comprised of a "backbone" that consists of a carbonylic acid (-COOH) and an amine group (-NH) linked together forming peptide bond (-C-NH-) In peptide, the amino acid residue on one end has an amine group (NL) on the & -carbon. This amino acid residue is called the N-terminal of the amino acid residue on the other end has a carbonglic acid group (-COOH) on the a-carbon. This amino acid is called the c-terminati Backbone of peptide the peptide Uz H-c-oo - CH -c-N-CH-C-NH-CH- th tyy СИ Cth CH -сі, C=0 N-tern Cle Ala Asn Leu C-terminal - Thank you!