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Human cytochrome P450 (P450) 27A1 catalyzes the hydroxylation of cholesterol and vitamin D derivatives. P450 27A1 is localized in the mitochondria and is reduced by its redox partner protein adrenodoxin twice for each catalytic cycle. The reliance on adrenodoxin is conserved across all human mitochondrial P450 enzymes. This study examines the adrenodoxin interaction with P450 27A1 and draws comparisons with studies of other P450 enzymes to determine if differences exist. The P450-adrenodoxin complex structure was examined by chemical crosslinking and analyzed by mass spectrometry. The effect of adrenodoxin concentration on P450 27A1 function was assessed by studying effects on steady state enzyme kinetics parameters and equilibrium substrate binding. The results suggest that adrenodoxin binds to P450 27A1 at a proximal site like other P450 enzymes but differs in the specific residues involved. Furthermore, the presence of adrenodoxin and/or substrate decreases the number of interprotein and intraprotein crosslinks observed, indicating that these components change the conformation of the P450 enzyme. Increased adrenodoxin concentration causes the P450 and vitamin D3 kcat value to increase, the kcat/Km value to decrease, and the substrate Kd to remain constant. These results suggest adrenodoxin alters enzyme efficiency beyond electron transfer without affecting substrate loading. The adrenodoxin effects on P450 27A1 kinetics and equilibrium constants differ from those of other human mitochondrial P450 enzymes. In total, these structural and functional studies suggest that while the general adrenodoxin binding site and function is conserved across P450 enzymes, the details and additional effects of this interaction vary. 

The utilization of remote operated vehicles (ROVs) has become essential across various subsea industries, such as oil and gas exploration and offshore wind energy, yet significant challenges remain in achieving effective human-ROV interaction. Despite advancements, ROV operations are hindered by complex control systems, high physical and cognitive demands on pilots, and a lack of sensory feedback mechanisms that fully convey the underwater environment’s dynamics. This study addresses these gaps by surveying ROV pilots and industry stakeholders to identify prevalent operational challenges, essential skills, and perspectives on integrating novel teleoperation technologies, including mixed reality and haptic feedback. Findings reveal a strong industry interest in technologies that enhance situational awareness and ease control demands, although concerns remain regarding practical integration and operator fatigue. By highlighting the critical skills required and potential benefits of human-centered augmentation systems, this study provides insights to inform future ergonomic designs, training frameworks, and technology development aimed at advancing safe and effective ROV teleoperation.