Shape and dimension. (a) Tropomyosin, a 70-kDa muscle protein, is a two-stranded α-helical coiled coil. Estimate the length of the molecule. (b) Suppose that a 40-residue segment of a protein folds into a two-stranded antiparallel β structure with a 4-residue hairpin turn. What is the longest dimension of this motif?

Shape and dimension. (a) Tropomyosin, a 70-kDa muscle protein, is a two-stranded α-helical coiled coil. Estimate the length of the molecule. (b) Suppose that a 40-residue segment of a protein folds into a two-stranded antiparallel β structure with a 4-residue hairpin turn. What is the longest dimension of this motif?

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter30: Protein Synthesis

Section: Chapter Questions

Problem 16P: The Energetic Cost of Peptide Elongation How many ATP equivalents are consumed for each amino acid...

See similar textbooks

Similar questions

. Consider a small protein containing 101 amino acid residues. The protein will have 200 bonds about which rotation can occur. Assume that three orientations are possible about each of these bonds. (a) Based on these assumptions, about how many random-coil conforma- tions will be possible for this protein? (b) The estimate obtained in (a) is surely too large. Give one reason why.
(a) Tropomyosin, a 70-kDa muscle protein, is a two-stranded α -helical coiled coil. Estimate the length of the molecule. (b) Suppose that a 40- residue segment of a protein folds into a two-stranded antiparallel β structure with a 4-residue hairpin turn. What is the longest dimension of this motif?
7 Protein structure.Circle one of the three amino acid sequences that is most likely to form a stable a-helix? RASKTARQ DASKTAEQ KPGKPAGQ In one sentence (that can be accompanied by a small picture) explain why?
TERTIARY STRUCTURE (A) (B) (C) Fg Eet Galand Sen 20e Figure 6. Examples of the arrangement of a-helices and B-sheets in folded protein domains. Copyright 2013 from Essential Cell Biology, 4th Edition by Alberts et al. Reproduced by permission of Garland Science/ Taylor & Francis LLC. Figure 6 shows three examples of how secondary structure elements can be arranged in relation to one another in the functional, folded form of a complete protein or one compact portion of a protein. The overall three-dimensional shape (or conformation) of a protein is its tertiary structure. • What do you think holds together the various secondary structural elements in a particular three-dimensional pattern? (Hint: Look back at Figure 5 - what is sticking out from the sides of the a-helices and B-strands?)
i. A schematic structure of the subunit of hemerythrin (an oxygen-binding protein from invertebrate animals) is shown to the right. (a) It has been found that in some of the a-helical regions of hemerythrin, about every third or fourth amino acid residue is a hydrophobic one. Suggest a structural reason for this finding. (b) What would be the effect of a mutation that placed a proline residue at point A in the structure?
a) Canonical forces in protein folding. Describe how these forces come into play when a protein folds. Why do are other intermolecular interactions important to fully understand folding processes?
2. Subunit Composition of a Protein. A protein has a molecular mass of 400 kDa when measured by size-exclusion chromatography ( F). When subjected to gel electrophoresis in the presence of sodium dodecyl sulfate (SDS), the protein gives three bands with molecular masses of 180, 160, and 60 kDa. When electrophoresis is carried out in the presence of SDS and dithiothreitol (=), three bands are again formed, this time with molecular masses of 160, 90, and 60 kDa. Determine the subunit composition of the protein. Note: dithiothreitol is a reagent to beak down the disulfide bonds.
Protein-4YU4 is given, choose a part of it (containing at least 30 amino acid residues), find the amino acid sequence (sequence in it), identify what functional groups the amino acid substitutes contain (carboxyl group and 2-position the Nitro group will form amide bonds, forming the covalent basic structure of the protein). What different interactions can occur between these functional groups? How will it relate to the spatial structure of the protein?
.A protein gives a single band on SDS gel electrophoresis, as shown in lanes 1 and 2 below. There is little if any effect from adding
Using Fig. as a guide, draw the complete structure of a nucleoside triphosphate before and after it becomes incorporated into a polynucleotide chain. Draw the structure that would result if the newly formed phosphodiester bond were hydrolyzed.
GT 3 A. Write the structure of the pentapeptide GLDSC. B. What is the complete name of this pentapeptide? Show a tertiary structure of ACGGC after a disulfide bond forms. A sample of an unknown peptide was divided into two aliquots. One aliquot was treated with trypsin; the other was treated with cyanogen bromide. Given the following sequences (N-terminal to C- terminal) of the resulting fragments, deduce the sequence of the original peptide. Trypsin treatment Asn-Thr-Trp-Met-lle-Lys Gly-Tyr-Met-Gln-Phe Val-Leu-Gly-Met-Ser-Arg Cyanogen bromide treatment Gln-Phe Val-Leu-Gly-Met lle-Lys-Gly-Tyr-Met Ser-Arg-Asn-Thr-Trp-Met
A. Write the structure of the following peptide at pH 5.0 and calculate its net charge at this pH. Asp-His-Tyr-Arg-Lys-Leu-Thr-Gln. Based on the pKa value of the ionizable groups. B. A polypeptide consisting only of L-glutamate residues (poly-L-glutamate) may have a random coil or helical structure depending on pH. Explain this behavior by indicating at what pH values the helical structure will be favored.