Banca de DEFESA: LUCAS HILARIO NOGUEIRA DE SOUSA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LUCAS HILARIO NOGUEIRA DE SOUSA
DATE: 17/03/2026
TIME: 09:00
LOCAL: Videoconferência
TITLE:

Structural Elucidation of Surugamides and their Interaction with Montmorillonite for Controlled Release Applications.

KEY WORDS:

Cyclic peptides; Surugamides; Molecular modeling; NMR spectroscopy; Montmorillonite; Peptide–clay interactions

PAGES: 164
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Síntese Orgânica
SUMMARY:

Cyclic peptides have gained prominence in pharmaceutical research due to their conformational stability, enzymatic resistance, and functional versatility. Among them, surugamides constitute a promising family of non-ribosomal cyclic octapeptides with reported biological activities but with poorly understood three-dimensional structures. The absence of reliable molecular models and crystallographic information limits the understanding of their behavior in complex environments, particularly at interfaces relevant to drug delivery systems. To overcome this limitation, an experimentally grounded molecular modeling protocol was developed and validated to investigate the conformational and interfacial behavior of surugamides. The methodology was first validated using ribifolin and gramicidin S as benchmark peptides with known crystal data. Crystal geometry optimization followed by molecular dynamics simulations demonstrated that the INTERFACE force field accurately reproduces intramolecular features and unit cell parameters, supporting its application to peptides without resolved models. Surugamides were then synthesized by solid-phase peptide synthesis (SPPS) and characterized by NMR spectroscopy. Experimental dihedral angles were used as restraints to construct reliable three-dimensional models within the validated framework. These models enabled the investigation of peptide interactions with montmorillonite, a clay mineral widely employed in pharmaceutical formulations. The simulations provided insights into how conformation, charge distribution, and protonation state influence adsorption and intercalation processes, contributing to the understanding of the relationship between molecular organization and interfacial behavior. This approach can also be extended to other cyclic peptides lacking crystallographic data and may assist in the rational design of peptide–clay systems for controlled release applications.

COMMITTEE MEMBERS:
Presidente - 1569526 - RENATA MENDONÇA ARAUJO
Interno - 1086214 - ANDERSON DOS REIS ALBUQUERQUE
Externa à Instituição - TAÍCIA PACHECO FILL - UNICAMP
Externo à Instituição - ADOLFO HENRIQUE DE MORAES SILVA - UFMG
Externo à Instituição - RODRIGO MOREIRA VERLY - UFVJM