Discovery and Synthetic Applications of a NAD(P)H-Dependent Reductive Aminase from .

Reductive amination is one of the most synthetically direct routes to access chiral amines. Several Imine Reductases (IREDs) have been discovered to catalyze reductive amination (Reductive Aminases or RedAms), yet they are dependent on the expensive phosphorylated nicotinamide adenine dinucleotide cofactor NADPH and usually more active at basic pH. Here, we describe the discovery and synthetic potential of an IRED from (RedAm) that catalyzes reductive amination between a series of medium to large carbonyl and amine compounds with conversions of up to >99% and 99% enantiomeric excess at neutral pH.

Biocatalytic synthesis of ribonucleoside analogues using nucleoside transglycosylase-2.

Ribonucleosides are essential building blocks used extensively in antiviral and oligonucleotide therapeutics. A major challenge in the further development of nucleoside analogues for therapeutic applications is access to scalable and environmentally sustainable synthetic strategies. This study uses the type II nucleoside 2'-deoxyribosyltransferase from (NDT-2) to prepare a suite of ribonucleoside analogues using naturally-occurring uridine and cytidine sugar donors.

Divergent Oxidation Reactions of E- and Z-Allylic Primary Alcohols by an Unspecific Peroxygenase.

Unspecific peroxygenases (UPOs) catalyze the selective oxygenation of organic substrates using only hydrogen peroxide as the external oxidant. The PaDa-I variant of the UPO from Agrocybe aegerita catalyses the oxidation of Z- and E-allylic alcohols with complementary selectivity, giving epoxide and carboxylic acid/aldehyde products respectively. Both reactions can be performed on preparative scale with isolated yields up to 80 %, and the epoxidations proceed with excellent enantioselectivity (>99 % ee).

Decellularized porcine dermal hydrogel enhances implant-based wound healing in the setting of irradiation.

Acellular Dermal Matrix (ADM) provides mechanical and soft tissue support in implant-based breast reconstruction, and has shown to modulate the healing response. However, skin flap necrosis, edema, and previous radiation therapy can hinder ADM integration. Effective biomaterial integration requires regulating the immune response, fibrosis, and adipocyte-driven functionalization.

Gram-scale enzymatic synthesis of 2'-deoxyribonucleoside analogues using nucleoside transglycosylase-2.

Nucleosides are pervasive building blocks that are found throughout nature and used extensively in medicinal chemistry and biotechnology. However, the preparation of base-modified analogues using conventional synthetic methodology poses challenges in scale-up and purification. In this work, an integrated approach involving structural analysis, screening and reaction optimization, is established to prepare 2'-deoxyribonucleoside analogues catalysed by the type II nucleoside 2'-deoxyribosyltransferase from (NDT-2).

Preparative scale Achmatowicz and aza-Achmatowicz rearrangements catalyzed by unspecific peroxygenase.

The unspecific peroxygenase (UPO) from (rUPO-PaDa-I-H) is an effective and practical biocatalyst for the oxidative expansion of furfuryl alcohols/amines on a preparative scale, using the Achmatowicz and aza-Achmatowicz reaction. The high activity and stability of the enzyme, which can be produced on a large scale as an air-stable lyophilised powder, renders it a versatile and scalable biocatalyst for the preparation of synthetically valuable 6-hydroxypyranones and dihydropiperidinones. In several cases, the biotransformation out-performed the analogous chemo-catalysed process, and operates under milder and greener reaction conditions.

A refined picture of the native amine dehydrogenase family revealed by extensive biodiversity screening.

Native amine dehydrogenases offer sustainable access to chiral amines, so the search for scaffolds capable of converting more diverse carbonyl compounds is required to reach the full potential of this alternative to conventional synthetic reductive aminations. Here we report a multidisciplinary strategy combining bioinformatics, chemoinformatics and biocatalysis to extensively screen billions of sequences in silico and to efficiently find native amine dehydrogenases features using computational approaches. In this way, we achieve a comprehensive overview of the initial native amine dehydrogenase family, extending it from 2,011 to 17,959 sequences, and identify native amine dehydrogenases with non-reported substrate spectra, including hindered carbonyls and ethyl ketones, and accepting methylamine and cyclopropylamine as amine donor.

Dosimetric comparison of proton therapy and CyberKnife in stereotactic body radiation therapy for liver cancers.

Stereotactic body radiation therapy (SBRT) has been increasingly used for the ablation of liver tumours. CyberKnife and proton beam therapy (PBT) are two advanced treatment technologies suitable to deliver SBRT with high dose conformity and steep dose gradients. However, there is very limited data comparing the dosimetric characteristics of CyberKnife to PBT for liver SBRT.

Unspecific Peroxygenase (UPO) can be Tuned for Oxygenation or Halogenation Activity by Controlling the Reaction pH.

Unspecific Peroxygenases (UPOs) are increasingly significant enzymes for selective oxygenations as they are stable, highly active and catalyze their reactions at the expense of only hydrogen peroxide as the oxidant. Their structural similarity to chloroperoxidase (CPO) means that UPOs can also catalyze halogenation reactions based upon the generation of hypohalous acids from halide and HO. Here we show that the halogenation and oxygenation modes of a UPO can be stimulated at different pH values.

Redox-reversible siderophore-based catalyst anchoring within cross-linked artificial metalloenzyme aggregates enables enantioselectivity switching.

The immobilisation of artificial metalloenzymes (ArMs) holds promise for the implementation of new biocatalytic reactions. We present the synthesis of cross-linked artificial metalloenzyme aggregates (CLArMAs) with excellent recyclability, as an alternative to carrier-based immobilisation strategies. Furthermore, iron-siderophore supramolecular anchoring facilitates redox-triggered cofactor release, enabling CLArMAs to be recharged with alternative cofactors for diverse selectivity.

SilE-R and SilE-S-DABB Proteins Catalying Enantiospecific Hydrolysis of Organosilyl Ethers.

Silyl ethers fulfil a fundamental role in synthetic organic chemistry as protecting groups and their selective cleavage is an important factor in their application. We present here for the first time two enzymes, SilE-R and SilE-S, which are able to hydrolyse silyl ethers. They belong to the stress-response dimeric A/B barrel domain (DABB) family and are able to cleave the Si-O bond with opposite enantiopreference.

The Impact of Social Determinants of Health on the Treatment of Distal Radius Fracture.

Background: Disparities in social determinants of health (SDH) have been shown to play an increasingly important role in the equitable delivery of health care. Distal radius fractures (DRFs) are among the most common upper-extremity injuries encountered. This study aims to examine the influence of economic, educational, social, environmental, and healthcare disparities on management of these injuries.

Broad Spectrum Enantioselective Amide Bond Synthetase from .

The synthesis of amide bonds is one of the most frequently performed reactions in pharmaceutical synthesis, but the requirement for stoichiometric quantities of coupling agents and activated substrates in established methods has prompted interest in biocatalytic alternatives. Amide Bond Synthetases (ABSs) actively catalyze both the ATP-dependent adenylation of carboxylic acid substrates and their subsequent amidation using an amine nucleophile, both within the active site of the enzyme, enabling the use of only a small excess of the amine partner. We have assessed the ability of an ABS from (ShABS) to couple a range of carboxylic acid substrates and amines to form amine products.

Divergent Cascade Ring-Expansion Reactions of Acryloyl Imides.

Macrocyclic and medium-sized ring ketones, lactones and lactams can all be made from common acryloyl imide starting materials through divergent, one-pot cascade ring-expansion reactions. Following either conjugate addition with an amine or nitromethane, or osmium(VIII)-catalysed dihydoxylation, rearrangement through a four-atom ring expansion takes place spontaneously to form the ring expanded products. A second ring expansion can also be performed following a second iteration of imide formation and alkene functionalisation/ring expansion.

Regional Anesthesia for Wrist Fractures and Dislocations: Are We Really Blocking Opioid Prescribing?

Background: The aim of this study was to evaluate the impact of regional anesthesia for the treatment of wrist fractures or dislocation on opioid prescription-filling patterns.

Methods: Patients undergoing surgery for hand and wrist fractures or dislocations from 2010 to 2018 were identified by using a national insurance claims database. Patients were stratified by procedures conducted with and without regional anesthesia.

Structure of the imine reductase from Ajellomyces dermatitidis in three crystal forms.

The NADPH-dependent imine reductase from Ajellomyces dermatitidis (AdRedAm) catalyzes the reductive amination of certain ketones with amine donors supplied in an equimolar ratio. The structure of AdRedAm has been determined in three forms. The first form, which belongs to space group P321 and was refined to 2.

The Mechanism of Cannabichromene and Cannabidiol Alone Versus in Combination in the Alleviation of Arthritis-Related Inflammation.

Background: Patients suffering from arthritis have limited treatment options for nonoperative management. In search of pain relief, patients have been taking over-the-counter cannabinoids. Cannabidiol (CBD) and cannabichromene (CBC) are minor cannabinoids with reported analgesic and anti-inflammatory properties and have been implicated as potential therapeutics for arthritis-related pain.

A Reductive Aminase Switches to Imine Reductase Mode for a Bulky Amine Substrate.

Imine reductases (IREDs) catalyze the asymmetric reduction of cyclic imines, but also in some cases the coupling of ketones and amines to form secondary amine products in an enzyme-catalyzed reductive amination (RedAm) reaction. Enzymatic RedAm reactions have typically used small hydrophobic amines, but many interesting pharmaceutical targets require that larger amines be used in these coupling reactions. Following the identification of IR77 from as a promising biocatalyst for the reductive amination of cyclohexanone with pyrrolidine, we have characterized the ability of this enzyme to catalyze couplings with larger bicyclic amines such as isoindoline and octahydrocyclopenta()pyrrole.

Preparative-Scale Biocatalytic Oxygenation of N-Heterocycles with a Lyophilized Peroxygenase Catalyst.

A lyophilized preparation of an unspecific peroxygenase variant from Agrocybe aegerita (rAaeUPO-PaDa-I-H) is a highly effective catalyst for the oxygenation of a diverse range of N-heterocyclic compounds. Scalable biocatalytic oxygenations (27 preparative examples, ca. 100 mg scale) have been developed across a wide range of substrates, including alkyl pyridines, bicyclic N-heterocycles and indoles.

Comparing the Catalytic and Structural Characteristics of a 'Short' Unspecific Peroxygenase (UPO) Expressed in Pichia pastoris and Escherichia coli.

Unspecific peroxygenases (UPOs) have emerged as valuable tools for the oxygenation of non-activated carbon atoms, as they exhibit high turnovers, good stability and depend only on hydrogen peroxide as the external oxidant for activity. However, the isolation of UPOs from their natural fungal sources remains a barrier to wider application. We have cloned the gene encoding an 'artificial' peroxygenase (artUPO), close in sequence to the 'short' UPO from Marasmius rotula (MroUPO), and expressed it in both the yeast Pichia pastoris and E.

Synthesis of Stereoenriched Piperidines via Chemo-Enzymatic Dearomatization of Activated Pyridines.

The development of efficient and sustainable methods for the synthesis of nitrogen heterocycles is an important goal for the chemical industry. In particular, substituted chiral piperidines are prominent targets due to their prevalence in medicinally relevant compounds and their precursors. A potential biocatalytic approach to the synthesis of this privileged scaffold would be the asymmetric dearomatization of readily assembled activated pyridines.

Use of Rectus Femoris Muscle Flap in Patients With Absent Profunda Femoris Vascular Flow.

Background: The rectus femoris (RF) muscle flap is an excellent choice for soft tissue coverage of complex wounds of the groin because of its reliable vascular anatomy and sufficient bulk allowing coverage of vascular anastomoses. The muscle receives its blood supply from the descending branch of the lateral femoral circumflex artery (dLFCA), which originates from the profunda femoris artery (PFA) in the proximal thigh. This case series reports 3 patients on whom pedicled RF muscle flaps were performed successfully despite known occlusion of the PFA preoperatively.

CyberKnife Xsight versus fiducial-based target-tracking: a novel 3D dosimetric comparison in a dynamic phantom.

Background: The CyberKnife Xsight lung-tracking system (XLTS) provides an alternative to fiducial-based target-tracking systems (FTTS) for non-small-cell lung cancer (NSCLC) patients without invasive fiducial insertion procedures. This study provides a method for 3D independent dosimetric verification of the accuracy of the FTTS compared to the XLTS without relying on log-files generated by the CyberKnife system.

Methods: A respiratory motion trace was taken from a 4D-CT of a real lung cancer patient and applied to a modified QUASAR™ respiratory motion phantom.

Oxalate Oxidase for In Situ H O -Generation in Unspecific Peroxygenase-Catalysed Drug Oxyfunctionalisations.

H O -driven enzymes are of great interest for industrial biotransformations. Herein, we show for the first time that oxalate oxidase (OXO) is an efficient in situ source of H O for one of these biocatalysts, which is known as unspecific peroxygenase (UPO). OXO is reasonably robust, produces only CO as a by-product and uses oxalate as a cheap sacrificial electron donor.

Inverting the Stereoselectivity of an NADH-Dependent Imine-Reductase Variant.

Imine reductases (IREDs) offer biocatalytic routes to chiral amines and have a natural preference for the NADPH cofactor. In previous work, we reported enzyme engineering of the ()-selective IRED from (NADH-IRED-) yielding a NADH-dependent variant with high catalytic efficiency. However, no IRED with NADH specificity and ()-selectivity in asymmetric reductions has yet been reported.