Calcium Activation Mechanism of a Noncanonical Aromatic L-Amino Acid Decarboxylase from Psilocybin Mushroom
Yi Wang, Tianjie Li, Erin S. Reynolds, Ziqi Wang, Michael P. Torrens-Spence, Jing‐ke Weng
Research Square April 28, 2025 preprint DOI: 10.21203/rs.3.rs-6329392/v1 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Computational and experimental study |
|---|---|
| Topics | Psilocybin |
| Keywords | Calcium Mechanism biology Mushroom Biochemistry Stereochemistry Hallucinogen Pharmacology Enzyme Food science Organic chemistry |
| Key findings | Calcium activation of PcncAAAD is primarily mediated by a metal-binding site at the N-terminal domain/CTD interface (site A), which stabilizes a lid-rim structure essential for substrate binding. |
Abstract
Abstract PcncAAAD is a calcium-activatable noncanonical aromatic L-amino acid decarboxylase (AAAD) featuring a unique appendage C-terminal domain (CTD) and two metal-binding sites. In this study, we establish an in silico RMSD-based evaluation model through molecular dynamics simulations, validated by in vitro enzyme assays, to decipher the enzyme’s calcium activation mechanism. Between the two metal-binding sites, the site at the N-terminal domain/CTD interface (site A) is found to play a primary role in the calcium activation of PcncAAAD, whereas the secondary site within the unique CTD (site B) contributes to the calcium-mediated stabilization of enzyme structure. Binding of calcium, but not sodium, exerts a profound influence on PcncAAAD activity by stabilizing a "lid-rim" structure underlying site A, which in turn maintains the integrity of the substrate-binding environment. In silico mutations disrupting site A or the “lid-rim” structure show severe structural distortion of the active site, leading to reduced or even eliminated activity as demonstrated by in vitro assays. Collectively, our computational and experimental analyses pinpoint the molecular mechanism underlying the noncanonical activation of PcncAAAD by calcium. These findings deepen our understanding of metal-activatable enzymes and hold promise for the rational design of engineered enzymes for the synthesis of aromatic amino acid derivatives.
Comparable studies
Other experimental studies on psilocybin, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Psilocybin induces schizophrenia-like psychosis in humans via a serotonin-2 agonist action Healthy human volunteers | 1998 | Experimental study | |
| Validation of the revised Mystical Experience Questionnaire in experimental sessions with psilocybin Participants in controlled laboratory experiments receiving a moderate to high oral... | 2015 | Validation study using pooled data from five laboratory experiments | n = 184 |
| Broadband Cortical Desynchronization Underlies the Human Psychedelic State Healthy human participants | 2013 | Experimental study | |
| Long-term follow-up of psilocybin-assisted psychotherapy for psychiatric and existential distress in patients with life-threatening cancer Participants with cancer-related psychiatric distress who completed a parent randomized... | 2020 | Long-term within-subjects follow-up analysis | n = 15 |
| Enzymatic Synthesis of Psilocybin | 2017 | Laboratory study |