Membrane-spanning proteins are notoriously difficult to characterize by x-ray crystallography.Hollonut of VISA Toplona. Explain how the information in the diagrams below can be used in the detection of membrane-spanning proteins consisting of alpha helices, given that the lipid portion of a typical bilayer isapproximately 30 Å thick.Amino terminus5.4 A(3.6 residues)b. Identify and briefly describe how the features of a transmembrane protein composed of ß-sheetsdiffer from that above.

The biological membranes consist of a bi-layer of phospholipid molecules.In addition, there membrane…

Answered: Membrane-spanning proteins are…

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

Bacteriorhodospin (Mw = 26 kDa) is a protein with purple colour. The protein acts as a light-activated proton pump that provides energy for cellular functions. The structure, revealed by both electron microscopy and X-ray crystallography, showed that the protein consists of 7 transmembrane spanning helices (TMH). Each TMH traverses the lipid bilayer completely (thickness of 45 Å). a)Calculate the minimum number of amino acid residues needed per TMH to completely cross the membrane. b)Estimate how large a fraction of the bacteriorhodopsin protein that is made up by TMHs. c)Now that you know the fraction of the protein that is made up by TMHs, at which ψ/φangles will the amino acids cluster in a Ramachandran plot?
Create a ROUGH SKETCH (no need for exact hydropathy indices and residue numbers) of the hydropathy plot for the given membrane protein. -coo Please follow the color assignment of the helical domains and properly label the plot and axes. Here is an example: Amino Outside terminus Transmembrane helices are predicted by hydrophobic stretches of 20-25 aa residues 10 50 100 150 200 250 Hydrophobic Inside Hydrophilic Carboxyl terminus -3 10 50 100 150 200 250 Residue number Bacteriorhodopsin Hydropathy index
Bacteriorhodopsin is an integral membrane protein containing 248 amino acids. X- ray analysis of this protein reveals that it consists of seven parallel a-helical segments, each of which traverses the bacterial cell membrane. Calculate the minimum number of amino acid residues necessary for a single a-helical segment to completely traverse the bacterial cell membrane (assume the membrane has a thickness of 4.1 nm). (a) (b) Estimate the fraction of the bacteriorhodopsin protein that is involved in membrane-spanning helices.
Roughly sketch the hydropathy plot for the given hypothetical membrane protein. Follow the color assignment of the helical domains and properly label your plot and axes (NB: Only a rough sketch is being asked. No need be exact with the hydropathy indices and residue numbers). CO-
Describe the general structure of a type 2 alpha helix protein. Explain how type 2 alpha helix transmembrane domains can be used to form pathways for large polar and charged molecules to traverse the lipid bilayer of the cell membrane.
Researchers have discovered a new membrane protein that has three transmembrane domain αhelixes that span the lipid bilayer.a. If the lipid bilayer is 30 Å thick, what is the smallest number of amino acid residues thatcan be in each α-helixes for them to be long enough to span the bilayer?
explain how a hydropathy plot can distinguish proteins with single transmembrane domains from those with multiple transmembrane domains
7. 1 B e here to search Required Study the two diagrams below. Diagram A 2 1 Diagram B 2 Based on the sequence of steps (1, 2, 3), which of the diagrams shows what would happen to proteins made at the ribosomes and transported to the outside of the cell? Diagram A Diagram B Both Diagram A and Diagram B Neither Diagram A nor Diagram B DELL 40)
Protein concentration can readily be determined using the Beer-Lambert law: A = e l c where A = absorbance e = molar absorption coefficient (M-1cm-1) l = light path length (cm) c = concentration (M) If the molar absorption coefficient at 280 nm for yeast ADH is 48860 M-1cm-1 and a 10 mL solution of the protein has an absorbance at 280 nm of 0.4 (as measured by a spectrometer with pathlength 1 cm), then what is the concentration of the protein solution (in μM)? i.e. concentration = ______ μM If the molecular weight of the protein is 36849, what is its concentration in mg/mL? i.e. concentration = _______ mg/mL For each part of the question, show your calculations to arrive at your answers.
Explain how both alpha helices and beta sheets can be used by proteins that cross membranes. Also explain what a hydropathy plot is and how such a plot can be used to differentiate transmembrane alpha helices from transmembrane beta sheets.
Monomeric, single-pass transmembrane proteins span a membrane with a single a helix that has characteristic chemical properties in the region of the bilayer. Which of the three 20-amino-acid sequences listed below is the most likely candidate for such a transmembrane segment? O TLIYFGVMAGVIGTILLIS O ITPIYFGPMAGVIGTPLLIS ITEIYFGRMAGVIGTDLLIS
A schematic diagram of the helical structure of cytochrome b562 is reproduced below. Thisprotein belongs to the family of -proteins that have a four-helix bundle. Number the helices 1 – 4according to their N  C direction. Indicate relative orientations of the macrodipoles of helices 1 – 4adjacent to the diagram of cytochrome b562. Remember that according to the definition of a dipolethat the arrow points towards the positive end.

SEE MORE QUESTIONS

Recommended textbooks for you

Biochemistry

ISBN:

9781319114671

Author:

Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:

W. H. Freeman

Lehninger Principles of Biochemistry

Biochemistry

ISBN:

9781464126116

Author:

David L. Nelson, Michael M. Cox

Publisher:

W. H. Freeman

Fundamentals of Biochemistry: Life at the Molecul…

Biochemistry

ISBN:

9781118918401

Author:

Donald Voet, Judith G. Voet, Charlotte W. Pratt

Publisher:

WILEY

Biochemistry

ISBN:

9781319114671

Author:

Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:

W. H. Freeman

Lehninger Principles of Biochemistry

Biochemistry

ISBN:

9781464126116

Author:

David L. Nelson, Michael M. Cox

Publisher:

W. H. Freeman

Fundamentals of Biochemistry: Life at the Molecul…

Biochemistry

ISBN:

9781118918401

Author:

Donald Voet, Judith G. Voet, Charlotte W. Pratt

Publisher:

WILEY

Biochemistry

ISBN:

9781305961135

Author:

Mary K. Campbell, Shawn O. Farrell, Owen M. McDougal

Publisher:

Cengage Learning

Biochemistry

ISBN:

9781305577206

Author:

Reginald H. Garrett, Charles M. Grisham

Publisher:

Cengage Learning

Fundamentals of General, Organic, and Biological …

Biochemistry

ISBN:

9780134015187

Author:

John E. McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. Peterson

Publisher:

PEARSON

SEE MORE TEXTBOOKS