Amino Acid Histidines Lab Report

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The R group for the amino acid histidine has a pKa of 6 or so. The structure shown on the slides is the conjugate base, even though it has no charge. Use the Henderson – Hasselbach equation (you will have to track it down) to determine what percentage of the histidines in a protein will likely be protonated (the acid form) at a pH of 7.0 and at 7.4 To the clear, your answer will have two numbers. Please show your work. 7.0=6 + log [His]/[His-H] → 7-6=log [His]/[His-H] → 1=log [His]/[His-H] → 10^1= [His]/[His-H] → 1/11 (100)= about 9% for pH=7.0 7.4= 6 + log [His]/[His-H] → 7.4-6=log [His]/[His-H] → 1.4=log [His]/[His-H] → 10^1.4= [His]/[His-H] → 25.12+1= 26.12 → 1/26.12 (100)= about 3.8% for pH=7.4 Proteins sometimes have a phosphate group attached to them. This occurs after the protein is made. This post-translational phosphorylation reaction requires a “phosphate donor”. Propose such a donor, the amino acid(s) to which the phosphate group is likely added, and write a net…show more content…
Be sure to mention the functional group(s) in the respective molecules which participate in the bonds you propose. Proteins generally stick out of the histones making interactions between the histone and DNA strand possible. Hydrogen bonds between the histone octamer and DNA strand usually happen because histones are generally composed of mostly positive amino acids like lysine and arginine. The part of the DNA backbone that interacts with the histone is the phosphate which is negatively charged. That makes these molecules drawn to each other. This lets the amino acids interact with DNA through electrostatic interactions. Viruses may have genomes that encode for as few as eight proteins. Will viral genomes likely contain DNA sequences that are similar to the host they commonly infect or is such similarity unlikely?

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