The amino acids Gly and Pro, as well as modified prolines th…
The amino acids Gly and Pro, as well as modified prolines that have a hydroxy group on the Pro ring or Hyp, are the principal amino acids comprising collagen. Consider this excerpt from this article: Destabilization of osteogenesis imperfecta collagen-like model peptides correlates with the identity of the residue replacing glycineKonrad Beck, Virginia C. Chan, Nigel Shenoy, Alan Kirkpatrick, John A. M. Ramshaw, and Barbara BrodskyPNAS April 11, 2000 97 (8) 4273-4278; https://doi.org/10.1073/pnas.070050097 “Gly-Pro-Hyp is the most common, as well as the most stabilizing, triplet in collagen (5). The presence of Gly at every third residue is considered essential….” If there is a genetic mutation that interrupts this pattern of Gly at every third position, bones do not develop properly. They are characteristically brittle, resulting in a genetic disease known as osteogenesis imperfecta. Use your knowledge of the structure of collagen to explain why this regularly repeating Gly residue is essential to the formation of a proper and strong collagen triple helix? (2 pts.) Vitamin C is required for the biochemical reaction that puts the modifying OH group on a Pro in collagen. Why does a vitamin C deficiency result in changing the overall strength of collagen? (2 pts.)
Read DetailsV-8 peptidase is an endopeptidase isolated from a strain of …
V-8 peptidase is an endopeptidase isolated from a strain of Staph. Aureus that cleaves a peptide bond on the carboxy side of acidic residuesin 50mM ammonium carbonate buffer at pH 8 . Treatment of peptides similar to the rattlesnake peptide with V-8 peptidase proceeds slowly, taking about 24 h to completely cleave or cut the peptide. However, if dithiothreitol (DTT) is added to the reaction in a 20 fold molar excess or BME (
Read DetailsIsoelectric focusing gel electrophoresis separates non-denat…
Isoelectric focusing gel electrophoresis separates non-denatured proteins and peptides by their isoelectric points using a pH gradient gel. Would you predict that this peptide would stop its travel through the gel in the acidic or basic portion of the gel? Briefly justify your choice.
Read DetailsIn the following procedure, the protein of interest, CA, is…
In the following procedure, the protein of interest, CA, is initially concentrated by precipitation from a 30% saturated ammonium sulfate solution. If you were interested in using ammonium sulfate precipitation to isolate a highly charged peptide, would you expect the peptide to precipitate from a low or high concentration ammonium sulfate in solution? Briefly justify your answer. Procedure from the reference cited below: “Briefly, cells expressing the wild-type CA protein were lysedthrough a microfluidizer. Soluble CA protein in the clarifiedlysate was concentrated by precipitation from 30% saturatedammonium sulfate. CA protein was redissolved in 50 mM Tris(pH 8.0) and functionally purified by the addition of sodiumchloride to a final concentration of 2.5 M. After two rounds offunctional purification, the wild-type CA protein wasresuspended in 50 mM sodium phosphate buffer (pH 7.5)and dialyzed against the same buffer. The dialyzed sample wasfurther purified by a subtractive anion exchange chromatography step using a Q-HP HiTrap column (catalog no. 17-1154-01, GE Healthcare, Piscataway, NJ). Purification of 2Mut and 4Mut CA mutants followed thesame protocol that was used for wild-type CA except that200 mM β-mercaptoethanol was included in all buffersthroughout the process. The functionally purified capsidmutant proteins were redissolved in 50 mM Tris (pH 7.5) and40 mM β-mercaptoethanol prior to dialysis in the same buffer,and a subsequent purification with subtractive anion exchangechromatography was performed.” A Trimer of Dimers Is the Basic Building Block for Human Immunodeficiency Virus-1 Capsid Assembly.
Read DetailsAn auditor selected items for test counts from the client’s…
An auditor selected items for test counts from the client’s warehouse during the physical inventory observation. The auditor then traced these test counts into the detailed inventory listing that ultimately agreed to the financial statements. This procedure most likely provided evidence concerning management’s assertion of
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