Subunit Composition of a Protein. A protein has a molecular mass of 400 kDa when measured by size-exclusion chromatography ( F). When subjected to gel electrophoresis in the presence of sodium dodecyl sulfate (SDS), the protein gives three bands with molecular masses of 180, 160, and 60 kDa. When electrophoresis is carried out in the presence of SDS and dithiothreitol (=), three bands are again formed, this time with molecular masses of 160, 90, and 60 kDa. Determine the subunit composition of the protein.

Subunit Composition of a Protein. A protein has a molecular mass of 400 kDa when measured by size-exclusion chromatography ( F). When subjected to gel electrophoresis in the presence of sodium dodecyl sulfate (SDS), the protein gives three bands with molecular masses of 180, 160, and 60 kDa. When electrophoresis is carried out in the presence of SDS and dithiothreitol (=), three bands are again formed, this time with molecular masses of 160, 90, and 60 kDa. Determine the subunit composition of the protein.

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter31: Completing The Protein Life Cycle: Folding, Processing, And Degradation

Section: Chapter Questions

Problem 3P: Understanding the Relevance of Chaperones in Protein Folding Protein molecules, like all molecules,...

See similar textbooks

Similar questions

Denaturation of Proteins The following are four levels of protein structures. Identify the inter- and intramolecular forces of attractions that stabilized each level. Level of Protein Structure Forces of Attraction Present Primary Secondary Tertiary Quaternary 2.) What is denaturation? 3.) What are denaturing agents? Give three examples and describe their effects on protein. 4.) Differentiate reversible and irreversible denaturation. 5.)Why is 70% ethanol is more effective than 100% ethanol to kill bacteria?
A protein is purified from a bacterium using Size Exclusion Chromatography (SEC), with a molecular weight of 200kD. When this protein is run on SDS-PAGE , a sing band is observed at 100kD. Based on these observations, what can be concluded about the structure of the protein? (if applies, choose more than one) The protein consist of two 200kD subiunits The protein has a quaternary structure The protein is madeup of two 100 kD subunits Proteins is a tetramer consisting of 200 kD domains. The protein contains an impurity of 100kD
2. A ligand binds more tightly to the folded state (N) of a protein than to the unfolded state (U). Show that the ligand stabilizes the protein and calculate by how much (ΔΔGfold = ?). Please help me find out deltadelta G fold.
1. Analysis of a peptide antibiotic purified from a strain of Bacillus brevii resulted in the following significant information: - Complete hydrolysis of the peptide yielded equimolar amounts of Leu, Orn, Phe, Pro, and Val - Molecular weight of the peptide was estimated to be aroung 1,200 Da - The peptide failed to undergo hydrolysis when treated with carboxypeptidase - Partial hydrolysis and then chromatographic separation of products yielded the following di- and tripeptides: Leu-Phe, Phe-Pro, Orn-Leu, Val-Orn, Val-Orn-Leu, Phe-Pro-Val, Pro-Val- - Orn Treament with dinitrofluorobenzene (DNFB) followed by complete hydrolysis yielded only free amino acids and the DNFB-derivatized ornithine at its side chain By using the above information, deduce the amino acid sequence of this peptide antibiotic. Write the final peptide sequence using 3-letter abbreviations. Show the complete and step by step solution.
Protein Structure and Function A common strategy in the regulation of protein function is to alter its structure. Describe two specific strategies used by the cell to alter a protein’s structure, thereby altering its function.
Predict the number of bands and apparent mol. wt. of the following proteins on SDS gels. 1. A trimeric protein containing three chains, each with a molecular weight of 60,000 Da (60 kDa).
. Pick all that are TRUE regarding analysis of quaternary structures of proteins using polyacrylamide electrophoresis:I. The added β-mercaptoethanol disrupts S--S bonds bridging the polypeptide chains causing the appearance of higher Rf bands compared to the native protein run. II. Heating up any protein before subjecting to SDS-PAGE will always result in the formation of more than one band.III. A good asymmetrical gel layout would be : (Lane 1) MW ladder, (2) native protein, (3) protein + β-ME, (4) protein + HCL, (5) protein + β-ME + HCl.IV. Formation of a single band in the protein + β-ME + HCl run, whose Rf is lower than the native run, could be indicative that the protein is a homodimer.A. I onlyB. I and IIC. II and IIVD. None is true
The vast majority of structures deposited in the Protein Databank (>95%) have been determined using NMR Hard keratins (such as in the skin) are less resistant to stretch because the larger number of disulfide bonds resist deformative forces. Structures produced by X-ray diffraction are as good as the solutions from which they are derived they are false and I know that but explain why they are false
Avidin exists as a protein complex of around 68 kDa. Research to determine the types of interactions that hold the avidin complex together. Based on your research, which molecular weight would you expect for avidin when treated with beta-mercaptoethanol and run through a native gel? 35 kDa 68 kDa 10 kDa 19 kDa
TRUE OR FALSE 35. Denaturation is basically the dis arrangement of intramolecular interactions in a tertiary structure of a protein. 36. When proteins are dissolved in water, alt polar regions are ionized.
Some proteins migrate anomalously in SDS-PAGE gels. For instance, the molecular weight determined from an SDS-PAGE gel is sometimes very different from the molecular weight determined from the amino acid sequence. Suggest an explanation for this discrepancy.
A protein has molecular mass of 200 kDa when measured by gel filtration. When subjected to SDS PAGE with and without 2-mercaptoethanol (2-ME) the gel shown below was obtained. What is the likely subunit composition of this protein and why? a. The protein has 4 subunits, with molecular masses 100, 50, 25, and 25 kDa. 25 kDa subunits are linked to each other via noncovalent interactions. b. The protein has 4 subunits, with molecular masses 100, 50, 25, and 25 kDa. 50 kDa subunit is linked to the one 25 kDa subunit via noncovalent interactions. c. The protein has 3 subunits, with molecular masses 100, 75 and 25 kDa that are linked by noncovalent interactions. d. The protein has 4 subunits, with molecular masses 100, 75, 50 and 25 kDa. The subunits are linked by disulfide bonds. e. The protein has 4 subunits, with molecular masses 100, 50, 25, and 25 kDa. 50 kDa subunit is linked to the one 25 kDa subunit by disulfide bonds.