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28Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of 29 coronavirus disease 2019 , is now pandemic with nearly three million cases 30 reported to date 1 . Although the majority of COVID-19 patients experience only mild or 31 moderate symptoms, a subset will progress to severe disease with pneumonia and acute 32 respiratory distress syndrome (ARDS) requiring mechanical ventilation 2 . Emerging results 33 indicate a dysregulated immune response characterized by runaway inflammation, 34including cytokine release syndrome (CRS), as the major driver of pathology in severe 35 -19 3,4 . With no treatments currently approved for COVID-19, therapeutics to 36 prevent or treat the excessive inflammation in severe disease caused by SARS-CoV-2 37 infection are urgently needed. Here, in 10 terminally-ill, critical COVID-19 patients we 38 report profound elevation of plasma IL-6 and CCL5 (RANTES), decreased CD8+ T cell 39 levels, and SARS-CoV-2 plasma viremia. Following compassionate care treatment with 40 the CCR5 blocking antibody leronlimab, we observed complete CCR5 receptor 41 occupancy on macrophage and T cells, rapid reduction of plasma IL-6, restoration of the 42 CD4/CD8 ratio, and a significant decrease in SARS-CoV-2 plasma viremia. Consistent 43 with reduction of plasma IL-6, single-cell RNA-sequencing revealed declines in 44 transcriptomic myeloid cell clusters expressing IL-6 and interferon-related genes. These 45 results demonstrate a novel approach to resolving unchecked inflammation, restoring 46 immunologic deficiencies, and reducing SARS-CoV-2 plasma viral load via disruption of 47 COVID MAIN TEXT 51 52Since the initial cases of COVID-19 were reported from Wuhan, China in December 53 2019 2 , SARS-CoV-2 has emerged as a global pandemic with an ever-increasing number 54 of severe cases requiring invasive external ventilation that threatens to overwhelm health 55

Bioactive peptides from Conus venom contain a natural abundance of post-translational modifications that affect their chemical diversity, structural stability, and neuroactive properties. These modifications have continually presented hurdles in their identification and characterization. Early endeavors in their analysis relied on classical biochemical techniques that have led to the progressive development and use of novel proteomic-based approaches. The critical importance of these post-translationally modified amino acids and their specific assignment cannot be understated, having impact on their folding, pharmacological selectivity, and potency. Such modifications at an amino acid level may also provide additional insight into the advancement of conopeptide drugs in the quest for precise pharmacological targeting. To achieve this end, a concerted effort between the classical and novel approaches is needed to completely elucidate the role of post-translational modifications in conopeptide structure and dynamics. This paper provides a reflection in the advancements observed in dealing with numerous and multiple post-translationally modified amino acids within conotoxins and conopeptides and provides a summary of the current techniques used in their identification.