Compute the pi of oligopeptide

Assignment Help Biology

Reference no: EM1383118

As Jung-Min Kee and Tom W. Muir noted in their recent review article (ACS Chem. Biol., 2012, 7 (1), pp 44–51), 2012 marked the 50th anniversary of the discovery of histidine phosphorylation in proteins. Post-translational phosphorylation of His residues at either the N-1 or N-3 positions of the imidazole group has been well recognized as an important signaling mechanism in prokaryotes and lower eukaryotes, and now is being associated with mammalian cellular processes, cancer, and inflammation. However its chemical lability especially at low pH has hindered its detection and study.

The RcsD protein of E. coli is part of a phosphorelay signal transduction system that accepts phosphate from RcsC on the His residue in the following target sequence: SDFAALAQTAHRLKGVFAMLN. Assume you have synthesized this sequence and achieved in vitro phosphorylation of its His by transfer from RcsC. Chemical characterization of both forms of the oligopeptide reveals the following pKas:

N- and C-terminal, 9.5 and 4.5, respectively; Asp side chain 3.5; Lys side chain 10.5; Arg side chain 12.0; and His side chain 6.0. Upon phosphorylation, the His imidazole pKa shifts to 6.5; the phospho group has pKas of 2.0 and 6.8.

a. On the single letter sequences of the His- and pHis-oligopeptides, indicate the charges the residues will carry at the pI points for the oligopeptides. Indicate partial charges (i.e., 10% - 90% charge) with ?+ and ?-.

Calculate the pI of each oligopeptide.
If the two oligopeptides were chromatographed on a DEAE-matrix at pH 7.5, in what order would they emerge? Explain why.
If the oligopeptides were reacted with cyanogen bromide, would their separation on the DEAE be changed? Explain why.

Reference no: EM1383118

Questions Cloud

Elucidate how do mission statements from international : Classroom conversation, no word or page limit: Elucidate how do mission statements from international businesses differ, and elucidate how they are similar

Describe how the swot matrix : Describe how the SWOT matrix, SPACE matrix, BCG matrix , IE matrix and Grand Strategy matrix are similar

Illustrate what is one share of this stock worth : The company announced today which it will continue to do this for another 2 years after which time it will discontinue paying dividends permanently. Illustrate what is one share of this stock worth today if the required rate of return is 16.5 perc..

Find the final speeds of the two objects : Two objects of masses m and 3.00 m are moving towards each other along the x-axis with the same initial speed of v. The object with mass m is travelling to the left.

Compute the pi of oligopeptide : As Jung-Min Kee and Tom W. Muir noted in their recent review article, 2012 marked the fifty anniversary of discovery of histidine phosphorylation in proteins.

Pastor tom was employed by the first church : Pastor Tom was employed by the First Church for 40 years. On Pastor Tom's retirement there was no adequate pension plan. Two months after the retirement, a wealthy parishioner.

Arrival of vehicles according to a poisson process : At a specified point on a highway, vehicles are known to arrive according to a Poisson process. Vehicles are counted in 20-second intervals, and vehicle counts are taken in 120 of these time intervals.

How to stop process-freeze its memory image in process : Some multicomputers permit running processes to be migrated from one node to another. Is it adequate to stop process, freeze its memory image, and just ship that off to different node?

Elucidate how does the prudent investor rule compare : Elucidate how does the prudent investor rule Compare/contrast versus prudent man rule pertaining to fiduciary duties of fund managers?

User Account

All Pages