Reference no: EM132439767

Problem:

Integral glycoprotein sequence, 195mer. (Note: amino acid sequence is broken into segments containing 10 amino acids, for ease in counting)

EQRHNSD [BFP] GGN (10) TKERYFLLVI (20) TLIFSFTILV (30) VAVLILLSYG (40) MHSDQMGDYF (50) FFIIILLLTS (60) VVVTYILGFF (70) SYKHMYRNEE (80) QAASTDD [GFP] FGH (90) GNHGVSRNRW (100) PHKTSYFFFI (110) LVVVASFILF (120) FSFIFIYSGG (130) KYTREFGDKG (140) SSADRPELIH (150) TREKHNWSLI (160) FFSFFVAVVS (170) ILLLFWSILI (180) LSYTSEKPLG (190) FKEEQ

Experimental comments:

A. Exposing the native membrane to an α-N-amino fluorescent labeling agent, demonstrated NO retention of fluorescence within this specific membrane protein.

B. Exposing the native membrane to cyanogen bromide (CNBr), we were able to isolate a peptide fragment that was carbohydrate positive.

C. Exposing the native membrane to tryptic digestion, we were able to isolate two peptide fragments that were carbohydrate positive.

D. The membrane protein DID NOT demonstrate FRET when exposed to 380 nm.

Questions:

(i) On the sequence above, draw a box around the areas which would represent membrane spanning domains in a native lipid bilayer.

(ii) Draw a cartoon of the predicted transmembrane protein as it would be found in the native lipid bilayer. Clearly label all features: N- and C-termini, approximate carbohydrate positioning, and enzyme cleavage sites used in defining protein orientation.

(iii) Draw a representative hydropathy plot for the above protein - Indicate the probable entrance/exit points from the membrane (using the above numbering system). Label the N- and C-termini and both axes.