東華大學圖書館 |

Examining the Interaction of the Antiviral Protein MxB with HIV Capsid.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Examining the Interaction of the Antiviral Protein MxB with HIV Capsid./
作者:	Smaga, Sarah S.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2019,
面頁冊數:	101 p.
附註:	Source: Dissertations Abstracts International, Volume: 81-01, Section: B.
Contained By:	Dissertations Abstracts International81-01B.
標題:	Biochemistry. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=13918040
ISBN:	9781392328705

Examining the Interaction of the Antiviral Protein MxB with HIV Capsid.
Smaga, Sarah S.

Examining the Interaction of the Antiviral Protein MxB with HIV Capsid. - Ann Arbor : ProQuest Dissertations & Theses, 2019 - 101 p.

Source: Dissertations Abstracts International, Volume: 81-01, Section: B.

Thesis (Ph.D.)--Yale University, 2019.

This item must not be added to any third party search indexes.

MxB is an interferon-induced restriction factor of HIV. It is localized to the nuclear periphery, near nuclear pores, and is thought to restrict the virus by interfering with nuclear import of the viral genome. MxB interacts with the HIV capsid, a protein shell that protects the viral genome. The capsid is composed of the protein CA, organized into hexamers and pentamers. Like many capsid-binding host factors, MxB senses the higher-level organization of CA in the capsid, but not individual CA proteins, CA hexamers, or CA pentamers. It is known that a triple-arginine motif in the N-terminus of MxB is responsible for its interaction with capsid, but the surfaces on capsid that mediate this interaction remain unknown. My dissertation research sought to understand how MxB recognizes the capsid lattice.In Chapter 2, I present an extensive biochemical study of MxB binding to capsid. I took advantage of property the CA protein that allows it to form helical tubes in solution, recreating the lattice organization of the capsid in cells. These helical tubes can be used in co-pelleting experiments to explore the binding of lattice-sensing host factors. I engineered mutations into these helical CA tubes and performed extensive scanning of the capsid lattice surfaces to define the MxB binding site. I found that MxB binding was sensitive to mutations at the interface between three hexamers and validated that previous mutations at this site disrupt binding in vitro. Furthermore, I was able to collaborate with the Perilla lab at the University of Delaware to perform all-atom simulations of an MxB peptide binding to a capsid surface. These simulations independently confirmed my observation that MxB binds to the interface between three hexamers. Residues which I identified biochemically as important for binding had high occupancy in the simulation as well.In Chapter 3, I sought to explore the observation that longer N-terminal MxB peptides displayed better binding to CA helical assemblies. I performed three experiments to investigate potential CA-binding regions outside the triple arginine motif. I investigated previous reports that different monkey species displayed differential MxB restriction of certain HIV capsids. I found no difference in the binding of MxB in vitro, suggesting that the region of MxB that differs in these species of monkeys does not have a substantial role in MxB-CA binding. I tested a putative CA-binding FG motif at residues 36-37 of MxB. I observed no reduction of MxB bound to CA in the presence of an FGlike compound known to bind CA at the FG-binding site, suggesting that the FG motif of MxB is not contributing to the observed better binding. Finally, I generated N-terminal truncations of MxB to map the potential CA-binding site and found that it may be present between residues 40-83 of MxB.In Chapter 4, I chronicle several attempts to solve a structure of the MxB-CA interaction. I soaked an MxB peptide into CA crystals containing the MxB binding site but found that the peptide bound at an axis of symmetry and is not visible in the structure. I generated multiple fusion constructs with MxB and other CA-binding factors, but none formed a monodisperse complex suitable for electron microscopy studies. Finally, I describe a construct that could be used to solve the structure of MxB bound to CA tubes that takes advantage of the helical symmetry of CA. These studies provide a substantial advancement in our understanding of how MxB interacts with the HIV capsid. This is the first report that connects the latticesensing ability of a CA-binding host factor to individual CA residues. The MxB binding site - the interface between three hexamers - is highly conserved, and likely plays an important role in capsid stability. This surface is a promising target for the development of antiviral compounds, perhaps inspired by the binding of MxB.

ISBN: 9781392328705Subjects--Topical Terms:

518028
Biochemistry.

Examining the Interaction of the Antiviral Protein MxB with HIV Capsid.
LDR:04999nmm a2200325 4500 001 2207779
005 20190920102421.5
008 201008s2019 ||||||||||||||||| ||eng d
020 $a 9781392328705
035 $a (MiAaPQ)AAI13918040
035 $a AAI13918040
040 $a MiAaPQ $c MiAaPQ
100 1 $a Smaga, Sarah S. $3 3434782
245 1 0 $a Examining the Interaction of the Antiviral Protein MxB with HIV Capsid.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2019
300 $a 101 p.
500 $a Source: Dissertations Abstracts International, Volume: 81-01, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
500 $a Advisor: Xiong, Yong.
502 $a Thesis (Ph.D.)--Yale University, 2019.
506 $a This item must not be added to any third party search indexes.
506 $a This item must not be sold to any third party vendors.
520 $a MxB is an interferon-induced restriction factor of HIV. It is localized to the nuclear periphery, near nuclear pores, and is thought to restrict the virus by interfering with nuclear import of the viral genome. MxB interacts with the HIV capsid, a protein shell that protects the viral genome. The capsid is composed of the protein CA, organized into hexamers and pentamers. Like many capsid-binding host factors, MxB senses the higher-level organization of CA in the capsid, but not individual CA proteins, CA hexamers, or CA pentamers. It is known that a triple-arginine motif in the N-terminus of MxB is responsible for its interaction with capsid, but the surfaces on capsid that mediate this interaction remain unknown. My dissertation research sought to understand how MxB recognizes the capsid lattice.In Chapter 2, I present an extensive biochemical study of MxB binding to capsid. I took advantage of property the CA protein that allows it to form helical tubes in solution, recreating the lattice organization of the capsid in cells. These helical tubes can be used in co-pelleting experiments to explore the binding of lattice-sensing host factors. I engineered mutations into these helical CA tubes and performed extensive scanning of the capsid lattice surfaces to define the MxB binding site. I found that MxB binding was sensitive to mutations at the interface between three hexamers and validated that previous mutations at this site disrupt binding in vitro. Furthermore, I was able to collaborate with the Perilla lab at the University of Delaware to perform all-atom simulations of an MxB peptide binding to a capsid surface. These simulations independently confirmed my observation that MxB binds to the interface between three hexamers. Residues which I identified biochemically as important for binding had high occupancy in the simulation as well.In Chapter 3, I sought to explore the observation that longer N-terminal MxB peptides displayed better binding to CA helical assemblies. I performed three experiments to investigate potential CA-binding regions outside the triple arginine motif. I investigated previous reports that different monkey species displayed differential MxB restriction of certain HIV capsids. I found no difference in the binding of MxB in vitro, suggesting that the region of MxB that differs in these species of monkeys does not have a substantial role in MxB-CA binding. I tested a putative CA-binding FG motif at residues 36-37 of MxB. I observed no reduction of MxB bound to CA in the presence of an FGlike compound known to bind CA at the FG-binding site, suggesting that the FG motif of MxB is not contributing to the observed better binding. Finally, I generated N-terminal truncations of MxB to map the potential CA-binding site and found that it may be present between residues 40-83 of MxB.In Chapter 4, I chronicle several attempts to solve a structure of the MxB-CA interaction. I soaked an MxB peptide into CA crystals containing the MxB binding site but found that the peptide bound at an axis of symmetry and is not visible in the structure. I generated multiple fusion constructs with MxB and other CA-binding factors, but none formed a monodisperse complex suitable for electron microscopy studies. Finally, I describe a construct that could be used to solve the structure of MxB bound to CA tubes that takes advantage of the helical symmetry of CA. These studies provide a substantial advancement in our understanding of how MxB interacts with the HIV capsid. This is the first report that connects the latticesensing ability of a CA-binding host factor to individual CA residues. The MxB binding site - the interface between three hexamers - is highly conserved, and likely plays an important role in capsid stability. This surface is a promising target for the development of antiviral compounds, perhaps inspired by the binding of MxB.
590 $a School code: 0265.
650 4 $a Biochemistry. $3 518028
650 4 $a Biophysics. $3 518360
690 $a 0487
690 $a 0786
710 2 $a Yale University. $3 515640
773 0 $t Dissertations Abstracts International $g 81-01B.
790 $a 0265
791 $a Ph.D.
792 $a 2019
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=13918040