Crystal structure of Staphylococcus aureus clumping factor A in complex with fibrinogen derived peptide and uses thereof
Inventors
Hook, Magnus • Ko, Ya-Ping • Smeds, Emanuel • GANESH, VANNAKAMBADI K.
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Assignees
Member
Texas A&M UniversityTexas A&M University, established in 1876 as Texas' first public institution of higher education, is one of the largest public universities in the United States and a globally recognized research leader. As a land-, sea-, and space-grant institution, Texas A&M is the flagship of The Texas A&M University System and a member of the Association of American Universities. The university is committed to developing leaders of character, fostering innovation, and serving communities through education, research, and outreach, guided by six core values: Respect, Excellence, Leadership, Loyalty, Integrity, and Selfless Service. Texas A&M offers more than 140 undergraduate and approximately 270 graduate and professional degree programs across 16 colleges and schools, with branch campuses in Galveston and Qatar. The university is renowned for its rich traditions, vibrant student life, robust academic support, and a strong culture of service and inclusivity. With a student body exceeding 79,000 and a global network of over 593,000 former students, Texas A&M consistently ranks among the top universities for value, innovation, and student experience. The Aggie way of life is rooted in tradition, community, and a commitment to academic and personal excellence.
Texas A&M University, established in 1876 as Texas' first public institution of higher education, is one of the largest public universities in the United States and a globally recognized research leader. As a land-, sea-, and space-grant institution, Texas A&M is the flagship of The Texas A&M University System and a member of the Association of American Universities. The university is committed to developing leaders of character, fostering innovation, and serving communities through education, research, and outreach, guided by six core values: Respect, Excellence, Leadership, Loyalty, Integrity, and Selfless Service. Texas A&M offers more than 140 undergraduate and approximately 270 graduate and professional degree programs across 16 colleges and schools, with branch campuses in Galveston and Qatar. The university is renowned for its rich traditions, vibrant student life, robust academic support, and a strong culture of service and inclusivity. With a student body exceeding 79,000 and a global network of over 593,000 former students, Texas A&M consistently ranks among the top universities for value, innovation, and student experience. The Aggie way of life is rooted in tradition, community, and a commitment to academic and personal excellence.
Publication Number
US-8280643-B2
Publication Date
2012-10-02
Expiration Date
2029-06-30
Abstract
The present invention provides a method for determining the structure of a microbial surface components recognizing adhesive matrix molecule in complex with fibrinogen, by providing a ClfA complexed with a fibrinogen gamma-peptide; determining a ClfA binding region of the fibrinogen gamma-peptide; determining one or more critical amino acid residues in the ClfA binding region of a native fibrinogen gamma-peptide that is critical for a ClfA:fibrinogen gamma-peptide interaction; determining one or more amino acid residues of the ClfA that binds to the ClfA binding region of the native fibrinogen gamma-peptide; modeling the structure of the ClfA binding region; determining the structure of the ClfA in complex with the :fibrinogen gamma-peptide interaction; and identifying one or more potential agent(s) that inhibit the ClfA:fibrinogen gamma-peptide interaction without affecting binding of other proteins to the fibrinogen gamma-peptide.
Core Innovation
The invention provides a method and structural characterization for determining the complex of Staphylococcus aureus clumping factor A (ClfA) with a fibrinogen (Fg) derived gamma-peptide, involving identification of critical amino acid residues in both ClfA and the fibrinogen gamma-peptide that mediate binding, computational modeling of their interaction, and identification of agents that inhibit this interaction without affecting other protein bindings to fibrinogen.
The invention addresses the problem posed by the lack of detailed structural understanding of how ClfA binds to fibrinogen, which is a major virulence factor in Staphylococcus aureus infections and a target for vaccine and therapeutic development. Current treatments face challenges due to antibiotic resistance and the need for new prevention and treatment strategies. Understanding ClfA-Fg interaction at the molecular level is critical to develop effective vaccines and therapeutic agents.
The invention also discloses an engineered stabilized closed conformation variant of ClfA that binds fibrinogen with higher affinity, which serves as an efficient vaccine candidate. Additionally, the invention includes anti-ClfA:fibrinogen antibodies that inhibit this interaction selectively, therapeutic agents comprising peptides or small molecules with modifications enhancing specificity and affinity to ClfA, and methods of vaccinating and treating bacterial infections caused by MSCRAMM:fibrinogen interactions.
Claims Coverage
The patent includes one independent claim describing a method for determining the structure of a microbial surface components recognizing adhesive matrix molecule (MSCRAMM), specifically ClfA, in complex with fibrinogen gamma-peptide, along with related inventive features.
Method for determining ClfA-fibrinogen gamma-peptide complex structure
A method comprising providing ClfA complexed with a fibrinogen gamma-peptide; determining the ClfA binding region on fibrinogen gamma-peptide; identifying critical amino acid residues in the fibrinogen gamma-peptide and ClfA that mediate interaction; modeling the structure of the binding region; performing computational modeling of ClfA sequence binding to fibrinogen; thereby determining the structure of the ClfA:fibrinogen gamma-peptide interaction; and identifying agents that inhibit this interaction without disrupting binding of other proteins to fibrinogen.
Identification of potential inhibitory agents with amino acid differences
Identifying potential agents that differ in at least one amino acid from the native fibrinogen gamma-peptide which inhibit ClfA:fibrinogen interaction without affecting other protein bindings to fibrinogen.
Use of control and substituted peptides to determine critical residues
Synthesizing control peptides with native fibrinogen sequence and substituted peptides differing by amino acids, then comparing their inhibition of ClfA binding to native fibrinogen to determine which residues are critical or less important for interaction.
Determining ClfA amino acid residues involved in binding
Determining amino acid residues in ClfA that bind fibrinogen gamma-peptide by comparing stability of native ClfA:fibrinogen complex with mutated complexes where fibrinogen peptide is derived from ClfA binding region.
Surface origin of ClfA
ClfA is present on the surface of Staphylococcus aureus, Staphylococcus lugdunensis, or Staphylococcus epidermidis.
Specific fibrinogen peptides
The native fibrinogen peptide used for interaction studies may include variants such as K406A, D410A, or combined K406A and D410A peptides.
Other proteins unaffected
Agents inhibiting ClfA:fibrinogen gamma-peptide interaction do not affect binding of other proteins, including integrin αIIbβ3, to fibrinogen gamma-peptide.
The claims cover a comprehensive method for structural characterization of ClfA-fibrinogen interaction, identification of critical residues by peptide substitution and stability comparison, and discovery of selective inhibitory agents that block ClfA binding without affecting other fibrinogen interactions, particularly specifying species and peptide variants involved.
Stated Advantages
Provides detailed structural characterization of ClfA binding to fibrinogen gamma-peptide, enabling targeted vaccine and therapeutic design.
Enables development of therapeutic agents that specifically inhibit ClfA:fibrinogen interaction without impairing platelet integrin αIIbβ3 binding.
Offers engineered stabilized (closed) ClfA variants with enhanced fibrinogen binding affinity suitable as efficient vaccine candidates.
Allows identification of selective peptide variants and antibodies that inhibit bacterial adhesion thereby helping prevent and treat staphylococcal infections.
Documented Applications
Design of ClfA targeted vaccines and therapeutic agents including monoclonal antibodies for prevention and treatment of Staphylococcus aureus and related infections.
Development of therapeutic agents such as peptides, fusion proteins, small molecule inhibitors, or antibodies that inhibit MSCRAMM:fibrinogen interaction selectively.
Use of engineered stabilized ClfA protein as an immunogen in vaccine formulations administered via various routes including subcutaneous, intravenous, intramuscular, intranasal, vaginal, or oral.
Methods of treating or preventing bacterial infections caused by MSCRAMM:fibrinogen interactions through administration of pharmacologically or immunologically effective amounts of compositions.
Computational modeling and structure-based identification of inhibitors targeting the ClfA:fibrinogen interaction.
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