Quinine Sulfate

There is growing research on the allosteric behaviour of proteins, including studies on allosteric mutations that contribute to human diseases and the development of allosteric drugs. Allostery also plays a key role in drug metabolism, an essential factor in drug development. However, population specific variations, particularly in 3D protein structures, remain understudied. This study focuses on CYP3A4, a key enzyme responsible for metabolizing over 50% of FDA-approved drugs and often linked to adverse drug reactions. Given the vast genetic diversity of Africa, we investigated 13 CYP3A4 alleles from African populations using post-molecular dynamics analyses, with 12 being single variations and one containing a double variation. Except for one, all allele variations were located away from the active site, suggesting allosteric effects. Our comparative analyses of reference and variant structures, through hydrogen bond interactions, dynamic residue network analysis and substrate channel dynamics, revealed notable differences at both global and residue levels. The *32-I335T variant showed the largest changes compared to the reference structure, while *3-M445T (near normal metabolizer) exhibited the least change, with other variants falling in between. The *32-I335T variant showed a distorted conformation in the radius of gyration, a distinct kink in the I helix with specific hydrogen bonds and altered channel patterns. The *12-L373F variant, associated with reduced metabolism of midazolam and quinine, showed increased rigidity in its vicinity, potentially interfering with catalytic activity. Our findings align with clinical and wet lab data, suggesting that our approaches could be applied to analyse variants without clinical evidence.

Traumatic stress leads to maladaptive avoidance behaviors and alcohol misuse in some people. In rats, predator odor ("traumatic") stress produces persistent avoidance of stress-paired contexts and escalated alcohol self-administration in some animals (Avoiders) but not others (Non-Avoiders), mirroring the individual differences in stress responsivity and alcohol misuse seen in humans. Here, we measured post-stress free-choice and aversion-resistant alcohol drinking, anxiety-related behavior, and lateral hypothalamus Crh, Crhr1, Crhr2, and Crhbp gene expression in male and female Avoiders, Non-Avoiders, and unstressed Controls. Male but not female Avoider rats escalated their free-choice alcohol intake after stress, and greater avoidance predicted greater aversion-resistant alcohol drinking. Using ultrasonic vocalizations (USVs) as a measure of affect, we found that Non-Avoider males emitted more low frequency USVs (<32 kHz) preceding, during, and following predator odor stress. Finally, quantification of Crh, Crhr1, Crhr2, and Crhbp gene expression in the LH revealed that male Avoider rats had elevated Crh expression than Non-Avoiders and Controls, and that greater LH Crh expression correlated with more avoidance behavior and more alcohol drinking. In females, greater expression of Crh, Crhr1, Crhr2, and Crhbp in the LH all predicted less anxiety-like behavior. Collectively, these results show that the relationship between stress, alcohol drinking, anxiety-like behavior, and the LH CRH system is sex- and subpopulation-specific.