Solved

Passage Interactions Between Positively Charged Histones and Negatively Charged Nucleic Acids

Question 49

Multiple Choice

Passage
Interactions between positively charged histones and negatively charged nucleic acids are altered by acetylation and methylation of histone subunits.  These different post-translational modifications are recognized by histone-binding proteins such as BROMO domain Adjacent to Zinc finger 2B (BAZ2B) .  BAZ2B has a net negative charge but contains a lysine-rich regulatory region between its two histone-binding domains.NMR data revealed potential interactions between BAZ2B and histone subunit H3 (Figure 1) .  Binding was confirmed by isothermal titration calorimetry (ITC) , which measures enthalpy of binding when a protein solution is titrated with ligand injections of equal volume and concentration.  Each injection results in a negative peak as heat is released.  Figure 2 shows ITC results when wild-type BAZ2B (WT) or BAZ2B with the regulatory region removed (10M+) were titrated with unmodified histone 3 (H3) or H3 that was acetylated at lysine-14 (H3K14ac) .  In each case, the Hill coefficient was approximately 1.To test binding in a biological setting (in vivo) , WT and 10M+ BAZ2B were extracted from cell lysates on affinity columns containing H3 or H3K14ac covalently attached to beads.  BAZ2B was then eluted and binding was quantified by Western blot (Figure 3) .
Passage Interactions between positively charged histones and negatively charged nucleic acids are altered by acetylation and methylation of histone subunits.  These different post-translational modifications are recognized by histone-binding proteins such as BROMO domain Adjacent to Zinc finger 2B (BAZ2B) .  BAZ2B has a net negative charge but contains a lysine-rich regulatory region between its two histone-binding domains.NMR data revealed potential interactions between BAZ2B and histone subunit H3 (Figure 1) .  Binding was confirmed by isothermal titration calorimetry (ITC) , which measures enthalpy of binding when a protein solution is titrated with ligand injections of equal volume and concentration.  Each injection results in a negative peak as heat is released.  Figure 2 shows ITC results when wild-type BAZ2B (WT) or BAZ2B with the regulatory region removed (10M+) were titrated with unmodified histone 3 (H3) or H3 that was acetylated at lysine-14 (H3K14ac) .  In each case, the Hill coefficient was approximately 1.To test binding in a biological setting (in vivo) , WT and 10M+ BAZ2B were extracted from cell lysates on affinity columns containing H3 or H3K14ac covalently attached to beads.  BAZ2B was then eluted and binding was quantified by Western blot (Figure 3) . <strong>Figure 1</strong>  Electrostatic interactions between H3 and BAZ2B amino acid residues <strong>Figure 2</strong>  ITC traces (A) and K<sub>d</sub> values (B) of WT BAZ2B and 10M+ BAZ2B titrated with either unmodified H3 or H3Ka4ac <strong>Figure 3</strong>  Western blot of BAZ2B recovered from unmodified or acetylated H3 columns Adapted from Kostrhon S, Kontaxis G, Kaufmann T, et al. A histone-mimicking interdomain linker in a multidomain protein modulates multivalent histone binding. J Biol Chem. 2017;292(43) :17643-17657. -Which statement best explains why the 10M+ form of BAZ2B binds H3 with greater affinity than its wild-type counterpart? A) The increased hydrophobicity of 10M+ BAZ2B induces stronger London forces with H3. B) The loss of positive charges on 10M+ BAZ2B improves its ionic interactions with H3. C) 10M+ BAZ2B is more readily acetylated than WT BAZ2B. D) WT BAZ2B is expressed at lower levels than 10M+ BAZ2B in vivo. Figure 1  Electrostatic interactions between H3 and BAZ2B amino acid residues
Passage Interactions between positively charged histones and negatively charged nucleic acids are altered by acetylation and methylation of histone subunits.  These different post-translational modifications are recognized by histone-binding proteins such as BROMO domain Adjacent to Zinc finger 2B (BAZ2B) .  BAZ2B has a net negative charge but contains a lysine-rich regulatory region between its two histone-binding domains.NMR data revealed potential interactions between BAZ2B and histone subunit H3 (Figure 1) .  Binding was confirmed by isothermal titration calorimetry (ITC) , which measures enthalpy of binding when a protein solution is titrated with ligand injections of equal volume and concentration.  Each injection results in a negative peak as heat is released.  Figure 2 shows ITC results when wild-type BAZ2B (WT) or BAZ2B with the regulatory region removed (10M+) were titrated with unmodified histone 3 (H3) or H3 that was acetylated at lysine-14 (H3K14ac) .  In each case, the Hill coefficient was approximately 1.To test binding in a biological setting (in vivo) , WT and 10M+ BAZ2B were extracted from cell lysates on affinity columns containing H3 or H3K14ac covalently attached to beads.  BAZ2B was then eluted and binding was quantified by Western blot (Figure 3) . <strong>Figure 1</strong>  Electrostatic interactions between H3 and BAZ2B amino acid residues <strong>Figure 2</strong>  ITC traces (A) and K<sub>d</sub> values (B) of WT BAZ2B and 10M+ BAZ2B titrated with either unmodified H3 or H3Ka4ac <strong>Figure 3</strong>  Western blot of BAZ2B recovered from unmodified or acetylated H3 columns Adapted from Kostrhon S, Kontaxis G, Kaufmann T, et al. A histone-mimicking interdomain linker in a multidomain protein modulates multivalent histone binding. J Biol Chem. 2017;292(43) :17643-17657. -Which statement best explains why the 10M+ form of BAZ2B binds H3 with greater affinity than its wild-type counterpart? A) The increased hydrophobicity of 10M+ BAZ2B induces stronger London forces with H3. B) The loss of positive charges on 10M+ BAZ2B improves its ionic interactions with H3. C) 10M+ BAZ2B is more readily acetylated than WT BAZ2B. D) WT BAZ2B is expressed at lower levels than 10M+ BAZ2B in vivo. Figure 2  ITC traces (A) and Kd values (B) of WT BAZ2B and 10M+ BAZ2B titrated with either unmodified H3 or H3Ka4ac
Passage Interactions between positively charged histones and negatively charged nucleic acids are altered by acetylation and methylation of histone subunits.  These different post-translational modifications are recognized by histone-binding proteins such as BROMO domain Adjacent to Zinc finger 2B (BAZ2B) .  BAZ2B has a net negative charge but contains a lysine-rich regulatory region between its two histone-binding domains.NMR data revealed potential interactions between BAZ2B and histone subunit H3 (Figure 1) .  Binding was confirmed by isothermal titration calorimetry (ITC) , which measures enthalpy of binding when a protein solution is titrated with ligand injections of equal volume and concentration.  Each injection results in a negative peak as heat is released.  Figure 2 shows ITC results when wild-type BAZ2B (WT) or BAZ2B with the regulatory region removed (10M+) were titrated with unmodified histone 3 (H3) or H3 that was acetylated at lysine-14 (H3K14ac) .  In each case, the Hill coefficient was approximately 1.To test binding in a biological setting (in vivo) , WT and 10M+ BAZ2B were extracted from cell lysates on affinity columns containing H3 or H3K14ac covalently attached to beads.  BAZ2B was then eluted and binding was quantified by Western blot (Figure 3) . <strong>Figure 1</strong>  Electrostatic interactions between H3 and BAZ2B amino acid residues <strong>Figure 2</strong>  ITC traces (A) and K<sub>d</sub> values (B) of WT BAZ2B and 10M+ BAZ2B titrated with either unmodified H3 or H3Ka4ac <strong>Figure 3</strong>  Western blot of BAZ2B recovered from unmodified or acetylated H3 columns Adapted from Kostrhon S, Kontaxis G, Kaufmann T, et al. A histone-mimicking interdomain linker in a multidomain protein modulates multivalent histone binding. J Biol Chem. 2017;292(43) :17643-17657. -Which statement best explains why the 10M+ form of BAZ2B binds H3 with greater affinity than its wild-type counterpart? A) The increased hydrophobicity of 10M+ BAZ2B induces stronger London forces with H3. B) The loss of positive charges on 10M+ BAZ2B improves its ionic interactions with H3. C) 10M+ BAZ2B is more readily acetylated than WT BAZ2B. D) WT BAZ2B is expressed at lower levels than 10M+ BAZ2B in vivo. Figure 3  Western blot of BAZ2B recovered from unmodified or acetylated H3 columns
Adapted from Kostrhon S, Kontaxis G, Kaufmann T, et al. A histone-mimicking interdomain linker in a multidomain protein modulates multivalent histone binding. J Biol Chem. 2017;292(43) :17643-17657.
-Which statement best explains why the 10M+ form of BAZ2B binds H3 with greater affinity than its wild-type counterpart?


A) The increased hydrophobicity of 10M+ BAZ2B induces stronger London forces with H3.
B) The loss of positive charges on 10M+ BAZ2B improves its ionic interactions with H3.
C) 10M+ BAZ2B is more readily acetylated than WT BAZ2B.
D) WT BAZ2B is expressed at lower levels than 10M+ BAZ2B in vivo.

Correct Answer:

verifed

Verified

Unlock this answer now
Get Access to more Verified Answers free of charge

Related Questions

Q44: Passage<br>The recent advent of multidrug-resistant Mycobacterium tuberculosis

Q45: Each of the following molecules can be

Q46: Passage<br>The bacterium Clostridium difficile secretes protein toxins

Q47: An infant who experiences seizures and has

Q48: Passage<br>The bacterium Clostridium difficile secretes protein toxins

Q50: Passage<br>The HIV-derived transactivator of transcription (Tat) is

Q51: Passage<br>Nerve cells must maintain the composition of

Q52: Passage<br>The Ankyrin repeat and SOCS box containing

Q53: Passage<br>The ABO blood groups are determined by

Q54: Passage<br>The ABO blood groups are determined by