The human commensal <i>Candida. albicans</i> is the most common fungal resident of the human microbiome. In healthy individuals this fungus occupies a budding morphology. During dysbiosis or immune incompetence, this fungus undergoes a morphological transition from a budding yeast to a hyphal format which results in long filamentous tails that invade human epithelial cells and if not successfully treated, cause lethal systemic infections. One of the most potent molecular activators for this morphological transition is the recognition of bacterial peptidoglycan (PG) fragments by the Leucine Rich Repeat (LRR) domain of the adenylyl cyclase Cyr1p. The Cyr1p receptor behaves as a Pathogen Recognition Receptor (PRR) in the fungi, and is one of the key determinants of the commensal and pathogenic states of this organism. With current limitations of available effective antifungal treatments, small molecule binding inhibitors could prove useful in controlling these difficult to treat infections in immune compromised individuals. In order to develop small molecule inhibitors for this receptor, it is imperative that we characterize the properties of this protein and determine the extent of the interactions between the LRR domain and PG fragments. In our efforts to characterize and define the interactions of this receptor and bacterial PG fragments such as Muramyl Tripeptide (MTP), we have identified this receptor as a peripheral membrane protein and have employed photoaffinity labeling (PAL) using a photoactivatable MTP-diazirine ligand to elucidate the binding pocket of the LRR domain. Here, biochemical evidence is provided which demonstrates that the Cyr1p receptor is a peripheral membrane protein. The membrane associated construct was employed in a series of chemical biology experiments utilizing photoaffinity labeling (PAL). To conduct these experiments, a photoactivatable MTP-diazirine ligand was synthesized and used to begin elucidation of the binding pocket of the LRR domain. These studies set the stage for learning about the binding pocket of this receptor, as well as the design of selective small molecule binding inhibitors.

Biochemical investigation of the adenylyl cyclase Cyr1p from the human commensal <i>Candida albicans</i>

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Biochemical investigation of the adenylyl cyclase Cyr1p from the human commensal Candida albicans