Plasmodium subtilisin-like protease 1 (SUB1): insights into the active-site structure, specificity and function of a pan-malaria drug target.

Release of the malaria merozoite from its host erythrocyte (egress) and invasion of a fresh cell are crucial steps in the life cycle of the malaria pathogen. Subtilisin-like protease 1 (SUB1) is a parasite serine protease implicated in both processes. In the most dangerous human malarial species, Plasmodium falciparum, SUB1 has previously been shown to have several parasite-derived substrates, proteolytic cleavage of which is important both for egress and maturation of the merozoite surface to enable invasion. Here we have used molecular modelling, existing knowledge of SUB1 substrates, and recombinant expression and characterisation of additional Plasmodium SUB1 orthologues, to examine the active site architecture and substrate specificity of P. falciparum SUB1 and its orthologues from the two other major human malaria pathogens Plasmodium vivax and Plasmodium knowlesi, as well as from the rodent malaria species, Plasmodium berghei. Our results reveal a number of unusual features of the SUB1 substrate binding cleft, including a requirement to interact with both prime and non-prime side residues of the substrate recognition motif. Cleavage of conserved parasite substrates is mediated by SUB1 in all parasite species examined, and the importance of this is supported by evidence for species-specific co-evolution of protease and substrates. Two peptidyl alpha-ketoamides based on an authentic PfSUB1 substrate inhibit all SUB1 orthologues examined, with inhibitory potency enhanced by the presence of a carboxyl moiety designed to introduce prime side interactions with the protease. Our findings demonstrate that it should be possible to develop 'pan-reactive' drug-like compounds that inhibit SUB1 in all three major human malaria pathogens, enabling production of broad-spectrum antimalarial drugs targeting SUB1

Synthesis of β-Amino-α-Ketoamides

Synthesis of β-Amino-α-Ketoamide

Synthesis of β-amino-α-ketoamides

β-Amino-α-ketoamides 1 are a class of compounds exhibiting biological activity as reversible covalent enzyme inhibitors. The representative examples are clinically approved drugs for the treatment of hepatitis C virus Boceprevir 2 and Telaprevir 3. β-Amino-α- ketoamide substructure is also found in a number of natural products, many of which display a remarkable biological activity. The methods for the synthesis of β-amino-α-ketoamide can be classified based on the key steps of the synthetic routes: from unsaturated amide involving epoxydation followed by a regioselective azidolysis; from esters involving aminohydroxylation; from adehydes via Passerini reaction, cyanohydrin formation, addition of the masked acylcyanide (MAC) reagent or orthothioester; from imines via addition of dithiolane derived from oxoacetic acid, addition of isoxazolyl-4-triflates or via azetidinone formation; from acids via acylation of (cyanomethylene) triphenylphosphorane (the Wasserman procedure), via acylfurane formation or via Dakin-West reaction; from nitroalkanes via Henry reaction. In this review, the information from the scientific literature published within the period from 1990 till 2014 for the synthesis of β-amino-α-ketoamides is covered and systematized according to the above mentioned key steps. - See more at: http://eurekaselect.com/124000#sthash.EUO9P7nm.dpu

Substrate derived peptidic α-ketoamides as inhibitors of the malarial protease PfSUB1.

Peptidic α-ketoamides have been developed as inhibitors of the malarial protease PfSUB1. The design of inhibitors was based on the best known endogenous PfSUB1 substrate sequence, leading to compounds with low micromolar to submicromolar inhibitory activity. SAR studies were performed indicating the requirement of an aspartate mimicking the P1' substituent and optimal P1-P4 length of the non-prime part. The importance of each of the P1-P4 amino acid side chains was investigated, revealing crucial interactions and size limitations

Substrate Derived Peptidic α-Ketoamides as Inhibitors of the Malarial Protease PfSUB1

Peptidic α-ketoamides have been developed as inhibitors of the malarial protease PfSUB1. The design of inhibitors was based on the best known endogenous PfSUB1 substrate sequence, leading to compounds with low micromolar to submicromolar inhibitory activity. SAR studies were performed indicating the requirement of an aspartate mimicking the P1′ substituent and optimal P1–P4 length of the non-prime part. The importance of each of the P1–P4 amino acid side chains was investigated, revealing crucial interactions and size limitations

Effect of Chronic Hematologic Malignancies on In-Hospital Outcomes of Patients With ST-Segment Elevation Myocardial Infarction.

In view of hemorrhagic and prothrombotic tendencies, ST-segment elevation myocardial infarction (STEMI) patients with chronic hematologic malignancies (CHM) are felt to be at a higher risk and hence denied standard reperfusion strategies. In-hospital outcomes of CHM patients presenting with STEMI are unclear. The Nationwide Inpatient Sample data files from 2003 to 2014 were used to extract adult patients who presented with a primary diagnosis of STEMI. Patients who had a diagnosis of CHM defined as chronic myelogenous leukemia, chronic lymphocytic leukemia, essential thrombocythemia, polycythemia vera, chronic monocytic leukemia, and multiple myeloma were identified. The primary study outcome measure was in-hospital mortality. Inverse probability weighting-adjusted binary logistic regression was performed to identify independent predictors of in-hospital mortality. Of 2,715,807 STEMI patients included in the final analyses, 11,974 (0.4%) patients had a diagnosis of CHM. Patients with CHM were significantly older, had a higher prevalence of co-morbidities, and had a significantly higher unadjusted in-hospital mortality (14.9% vs 9.0%;

Effect of Chronic Hematologic Malignancies on In-Hospital Outcomes of Patients With ST-Segment Elevation Myocardial Infarction.

In view of hemorrhagic and prothrombotic tendencies, ST-segment elevation myocardial infarction (STEMI) patients with chronic hematologic malignancies (CHM) are felt to be at a higher risk and hence denied standard reperfusion strategies. In-hospital outcomes of CHM patients presenting with STEMI are unclear. The Nationwide Inpatient Sample data files from 2003 to 2014 were used to extract adult patients who presented with a primary diagnosis of STEMI. Patients who had a diagnosis of CHM defined as chronic myelogenous leukemia, chronic lymphocytic leukemia, essential thrombocythemia, polycythemia vera, chronic monocytic leukemia, and multiple myeloma were identified. The primary study outcome measure was in-hospital mortality. Inverse probability weighting-adjusted binary logistic regression was performed to identify independent predictors of in-hospital mortality. Of 2,715,807 STEMI patients included in the final analyses, 11,974 (0.4%) patients had a diagnosis of CHM. Patients with CHM were significantly older, had a higher prevalence of co-morbidities, and had a significantly higher unadjusted in-hospital mortality (14.9% vs 9.0%;

Quinoxaline-Based Inhibitors of Malarial Protease Pfsub1

2,3-Bis(phenylamino)quinoxalines have been identified as a novel class of malarial protease PfSUB1 inhibitors by screening of Malaria Box compounds. The synthesis of analog series and investigation of their inhibitory activity provided preliminary structure-activity relationship to create in silico models for binding of these compounds into the active site of PfSUB1

Quinoxaline-Based Inhibitors of Malarial Protease PfSUB1

2,3-Bis(phenylamino)quinoxalines have been identified as a novel class of malarial protease PfSUB1 inhibitors by screening of Malaria Box compounds. The synthesis of analog series and investigation of their inhibitory activity provided preliminary structure-activity relationship to create in silico models for binding of these compounds into the active site of PfSUB1