Molecular mechanism of androgen receptor mutation in multigenerational mild androgen insensitivity syndrome.

Objective: Androgen insensitivity syndrome (AIS) due to androgen receptor (AR) mutations creates a spectrum of clinical presentations based on residual AR function with the mildest impairment creating mild AIS (MAIS) whose undefined molecular mechanism and subtle clinical features leave it less understood and underdiagnosed.

Design: In silico modeling and in vitro androgen bioassay of the mutated AR are used to identify its structural and physiological mechanism. Clinical features and responses to high-dose testosterone treatment of three cases of MAIS across a six-generation family pedigree are described.

Modulating antibody effector functions by Fc glycoengineering.

Antibody based drugs, including IgG monoclonal antibodies, are an expanding class of therapeutics widely employed to treat cancer, autoimmune and infectious diseases. IgG antibodies have a conserved N-glycosylation site at Asn297 that bears complex type N-glycans which, along with other less conserved N- and O-glycosylation sites, fine-tune effector functions, complement activation, and half-life of antibodies. Fucosylation, galactosylation, sialylation, bisection and mannosylation all generate glycoforms that interact in a specific manner with different cellular antibody receptors and are linked to a distinct functional profile.

Mass Spectrometry-Based Methods to Determine the Substrate Specificities and Kinetics of N-Linked Glycan Hydrolysis by Endo-β-N-Acetylglucosaminidases.

Glycosylation is a common posttranslational modification of proteins and refers to the covalent addition of glycans, chains of polysaccharides, onto proteins producing glycoproteins. The glycans influence the structure, function, and stability of proteins. They also play an integral role in the immune system, and aberrantly glycosylated proteins have wide ranging effects, including leading to diseases such as autoimmune conditions and cancer.

A Guide to In Silico Drug Design.

The drug discovery process is a rocky path that is full of challenges, with the result that very few candidates progress from hit compound to a commercially available product, often due to factors, such as poor binding affinity, off-target effects, or physicochemical properties, such as solubility or stability. This process is further complicated by high research and development costs and time requirements. It is thus important to optimise every step of the process in order to maximise the chances of success.

The role of adjuvants in overcoming antibacterial resistance due to enzymatic drug modification.

Antibacterial resistance is a prominent issue with monotherapy often leading to treatment failure in serious infections. Many mechanisms can lead to antibacterial resistance including deactivation of antibacterial agents by bacterial enzymes. Enzymatic drug modification confers resistance to β-lactams, aminoglycosides, chloramphenicol, macrolides, isoniazid, rifamycins, fosfomycin and lincosamides.

Mechanism of cooperative N-glycan processing by the multi-modular endoglycosidase EndoE.

Bacteria produce a remarkably diverse range of glycoside hydrolases to metabolize glycans from the environment as a primary source of nutrients, and to promote the colonization and infection of a host. Here we focus on EndoE, a multi-modular glycoside hydrolase secreted by Enterococcus faecalis, one of the leading causes of healthcare-associated infections. We provide X-ray crystal structures of EndoE, which show an architecture composed of four domains, including GH18 and GH20 glycoside hydrolases connected by two consecutive three α-helical bundles.

Sculpting therapeutic monoclonal antibody N-glycans using endoglycosidases.

Immunoglobulin G (IgG) monoclonal antibodies are a prominent and expanding class of therapeutics used for the treatment of diverse human disorders. The chemical composition of the N-glycan on the fragment crystallizable (Fc) region determines the effector functions through interaction with the Fc gamma receptors and complement proteins. The chemoenzymatic synthesis using endo-β-N-acetylglucosaminidases (ENGases) emerged as a strategy to obtain antibodies with customized glycoforms that modulate their therapeutic activity.

Understanding Hygroscopicity of Theophylline a Novel Cocrystal Polymorph: A Charge Density Study.

The charge density distribution in a novel cocrystal (1) complex of 1,3-dimethylxanthine (theophylline) and propanedioic acid (malonic acid) has been determined. The molecules crystallize in the triclinic, centrosymmetric space group 1̅, with four independent molecules ( = 4) in the asymmetric unit (two molecules each of theophylline and malonic acid). Theophylline has a notably high hygroscopic nature, and numerous cocrystals have shown a significant improvement in stability to humidity.

GH18 endo-β-N-acetylglucosaminidases use distinct mechanisms to process hybrid-type N-linked glycans.

N-glycosylation is one of the most abundant posttranslational modifications of proteins, essential for many physiological processes, including protein folding, protein stability, oligomerization and aggregation, and molecular recognition events. Defects in the N-glycosylation pathway cause diseases that are classified as congenital disorders of glycosylation. The ability to manipulate protein N-glycosylation is critical not only to our fundamental understanding of biology but also for the development of new drugs for a wide range of human diseases.

Tricyclic heterocycles display diverse sensitivity to the A147T TSPO polymorphism.

The 18 kDa translocator protein (TSPO) is a target for the development of imaging agents to detect neuroinflammation. The clinical utility of second-generation TSPO ligands has been hindered by the presence of a polymorphism, rs6971, which causes a non-conservative substitution of alanine for threonine at amino acid residue 147 (TSPO A147T). Given the complex nature of TSPO binding, and the lack of non-discriminating high-affinity ligands at both wild type and A147T forms of TSPO, a series of novel TSPO ligands containing various heterocyclic scaffolds was developed to explore the pharmacophoric drivers of affinity loss at TSPO A147T.

Structural basis of mammalian high-mannose N-glycan processing by human gut Bacteroides.

The human gut microbiota plays a central role not only in regulating the metabolism of nutrients but also promoting immune homeostasis, immune responses and protection against pathogen colonization. The genome of the Gram-negative symbiont Bacteroides thetaiotaomicron, a dominant member of the human intestinal microbiota, encodes polysaccharide utilization loci PULs, the apparatus required to orchestrate the degradation of a specific glycan. EndoBT-3987 is a key endo-β-N-acetylglucosaminidase (ENGase) that initiates the degradation/processing of mammalian high-mannose-type (HM-type) N-glycans in the intestine.

Structural insights into the mechanisms and specificities of IgG-active endoglycosidases.

The conserved N-glycan on Asn297 of immunoglobulin G (IgG) has significant impacts on antibody effector functions, and is a frequent target for antibody engineering. Chemoenzymatic synthesis has emerged as a strategy for producing antibodies with homogenous glycosylation and improved effector functions. Central to this strategy is the use of enzymes with activity on the Asn297 glycan.

Exploring the Binding of Barbital to a Synthetic Macrocyclic Receptor. A Charge Density Study.

Experimental charge density distribution studies, complemented by quantum mechanical theoretical calculations, of a host-guest system composed of a macrocycle (1) and barbital (2) in a 1:1 ratio (3) have been carried out via high-resolution single-crystal X-ray diffraction. The data were modeled using the conventional multipole model of electron density according to the Hansen-Coppens formalism. The asymmetric unit of macrocycle 1 contained an intraannular ethanol molecule and an extraannular acetonitrile molecule, and the asymmetric unit of 3 also contained an intraannular ethanol molecule.

A comparison of the experimental and theoretical charge density distributions in two polymorphic modifications of piroxicam.

Experimental charge density distribution studies of two polymorphic forms of piroxicam, β-piroxicam (1) and piroxicam monohydrate (2), were carried out via high-resolution single crystal X-ray diffraction experiments and multipole refinement. The asymmetric unit of (2) consists of two discrete piroxicam molecules, (2a) and (2b), and two water molecules. Geometry differs between (1) and (2) due to the zwitterionic nature of (2) which results in the rotation of the pyridine ring around the C(10)-N(2) bond by approximately 180°.

Correction: Experimental and theoretical charge density distribution in Pigment Yellow 101.

Correction for 'Experimental and theoretical charge density distribution in Pigment Yellow 101' by Jonathan J. Du et al., Phys.

Experimental and theoretical charge density distribution in Pigment Yellow 101.

The charge density distribution in 2,2'-dihydroxy-1,1'-naphthalazine (Pigment Yellow 101; P.Y.101) has been determined using high-resolution X-ray diffraction and multipole refinement, along with density functional theory calculations.