N-acetylmuramic acid recognition by MurK kinase from the MurNAc auxotrophic oral pathogen Tannerella forsythia.

The bacterial cell wall consists of a three-dimensional peptidoglycan layer, composed of peptides linked to the sugars N-acetylmuramic acid (MurNAc) and GlcNAc. Unlike other bacteria, the pathogenic Tannerella forsythia, a member of the red complex group of bacteria associated with the late stages of periodontitis, lacks biosynthetic pathways for MurNAc production and therefore obtains MurNAc from the environment. Sugar kinases play a crucial role in the MurNAc recycling process, activating the sugar molecules by phosphorylation.

A basidomycetous hydroxynaphthalene-prenylating enzyme exhibits promiscuity toward prenyl donors.

The fungal prenyltransferase ShPT from Stereum hirsutum was believed to prenylate 4-hydroxybenzyl alcohol and thereby be involved in the vibralactone biosynthesis. In this study, we demonstrate that hydroxynaphthalenes instead of benzyl alcohol or aldehyde were accepted by ShPT for regular C-prenylation in the presence of both dimethylallyl and geranyl diphosphate. Although the natural substrate of ShPT remains unknown, our results provide one additional prenyltransferase from basidiomycetes, which are less studied, in comparison to those from other sources.

Exploring divalent conjugates of 5--acetyl-neuraminic acid as inhibitors of coxsackievirus A24 variant (CVA24v) transduction.

Coxsackievirus A24 variant (CVA24v) is responsible for several outbreaks and two pandemics of the highly contagious eye infection acute hemorrhagic conjunctivitis (AHC). Currently, neither prevention (vaccines) nor treatments (antivirals) are available for combating this disease. CVA24v attaches to cells by binding Neu5Ac-containing glycans on the surface of cells which facilitates entry.

Exploring the Effect of Structure-Based Scaffold Hopping on the Inhibition of Coxsackievirus A24v Transduction by Pentavalent N-Acetylneuraminic Acid Conjugates.

Coxsackievirus A24 variant (CVA24v) is the primary causative agent of the highly contagious eye infection designated acute hemorrhagic conjunctivitis (AHC). It is solely responsible for two pandemics and several recurring outbreaks of the disease over the last decades, thus affecting millions of individuals throughout the world. To date, no antiviral agents or vaccines are available for combating this disease, and treatment is mainly supportive.

NeutrobodyPlex-monitoring SARS-CoV-2 neutralizing immune responses using nanobodies.

In light of the COVID-19 pandemic, there is an ongoing need for diagnostic tools to monitor the immune status of large patient cohorts and the effectiveness of vaccination campaigns. Here, we present 11 unique nanobodies (Nbs) specific for the SARS-CoV-2 spike receptor-binding domain (RBD), of which 8 Nbs potently inhibit the interaction of RBD with angiotensin-converting enzyme 2 (ACE2) as the major viral docking site. Following detailed epitope mapping and structural analysis, we select two inhibitory Nbs, one of which binds an epitope inside and one of which binds an epitope outside the RBD:ACE2 interface.

Reprogramming Substrate and Catalytic Promiscuity of Tryptophan Prenyltransferases.

Prenylation is a process widely prevalent in primary and secondary metabolism, contributing to functionality and chemical diversity in natural systems. Due to their high regio- and chemoselectivities, prenyltransferases are also valuable tools for creation of new compounds by chemoenzymatic synthesis and synthetic biology. Over the last ten years, biochemical and structural investigations shed light on the mechanism and key residues that control the catalytic process, but to date crucial information on how certain prenyltransferases control regioselectivity and chemoselectivity is still lacking.

Pentavalent Sialic Acid Conjugates Block Coxsackievirus A24 Variant and Human Adenovirus Type 37-Viruses That Cause Highly Contagious Eye Infections.

Coxsackievirus A24 variant (CVA24v) and human adenovirus 37 (HAdV-37) are leading causative agents of the severe and highly contagious ocular infections acute hemorrhagic conjunctivitis and epidemic keratoconjunctivitis, respectively. Currently, neither vaccines nor antiviral agents are available for treating these diseases, which affect millions of individuals worldwide. CVA24v and HAdV-37 utilize sialic acid as attachment receptors facilitating entry into host cells.

Structure of Merkel Cell Polyomavirus Capsid and Interaction with Its Glycosaminoglycan Attachment Receptor.

Merkel cell polyomavirus (MCPyV) is a human double-stranded DNA tumor virus. MCPyV cell entry is unique among members of the polyomavirus family as it requires the engagement of two types of glycans, sialylated oligosaccharides and sulfated glycosaminoglycans (GAGs). Here, we present crystallographic and cryo-electron microscopic structures of the icosahedral MCPyV capsid and analysis of its glycan interactions via nuclear magnetic resonance (NMR) spectroscopy.

Author Correction: Structural basis of cell wall peptidoglycan amidation by the GatD/MurT complex of Staphylococcus aureus.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Complete Decoration of the Indolyl Residue in cyclo-l-Trp-l-Trp with Geranyl Moieties by Using Engineered Dimethylallyl Transferases.

Mutation of the gatekeeping residues for prenyl donor selectivity in six dimethylallyl transferases significantly increased their activities toward geranyl diphosphate. Forty-two geranylated derivatives were obtained from 15 cyclic dipeptides by using the engineered enzymes. Taking cyclo-l-Trp-l-Trp as an example, the geranyl moiety can be attached to all seven possible positions of the indole nucleus.

Structure-based protein engineering enables prenyl donor switching of a fungal aromatic prenyltransferase.

Microorganisms provide valuable enzyme machinery to assemble complex molecules. Fungal prenyltransferases (PTs) typically catalyse highly regiospecific prenylation reactions that are of significant pharmaceutical interest. While the majority of PTs accepts dimethylallyl diphosphate (DMAPP), very few such enzymes can use geranyl diphosphate (GPP) or farnesyl diphosphate (FPP) as donors.

Structural basis of cell wall peptidoglycan amidation by the GatD/MurT complex of Staphylococcus aureus.

The peptidoglycan of Staphylococcus aureus is highly amidated. Amidation of α-D-isoglutamic acid in position 2 of the stem peptide plays a decisive role in the polymerization of cell wall building blocks. S.

Role of enhanced receptor engagement in the evolution of a pandemic acute hemorrhagic conjunctivitis virus.

Acute hemorrhagic conjunctivitis (AHC) is a painful, contagious eye disease, with millions of cases in the last decades. Coxsackievirus A24 (CV-A24) was not originally associated with human disease, but in 1970 a pathogenic "variant" (CV-A24v) emerged, which is now the main cause of AHC. Initially, this variant circulated only in Southeast Asia, but it later spread worldwide, accounting for numerous AHC outbreaks and two pandemics.

Myosin-1E interacts with FAK proline-rich region 1 to induce fibronectin-type matrix.

Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase involved in development and human disease, including cancer. It is currently thought that the four-point one, ezrin, radixin, moesin (FERM)-kinase domain linker, which contains autophosphorylation site tyrosine (Y) 397, is not required for in vivo FAK function until late midgestation. Here, we directly tested this hypothesis by generating mice with FAK Y397-to-phenylalanine (F) mutations in the germline.

Structural basis of head to head polyketide fusion by CorB.

Corallopyronin A is a polyketide derived from the myxobacterium with potent antibiotic features. The gene cluster responsible for the biosynthesis of corallopyronin A has been described recently, and it was proposed that CorB acts as a ketosynthase to interconnect two polyketide chains in a rare head-to-head condensation reaction. We determined the structure of CorB, the interconnecting polyketide synthase, to high resolution and found that CorB displays a thiolase fold.

Insights into Structure-Activity Relationships of Bacterial RNA Polymerase Inhibiting Corallopyronin Derivatives.

The new compound precorallopyronin A is a stable precursor in the biosynthesis of the antibiotic corallopyronin A. This natural product was isolated from the producer strain Corallococcus coralloides B035. Together with various semisynthetically obtained corallopyronin A derivatives its antibacterial effects were evaluated.

Site-directed mutagenesis switching a dimethylallyl tryptophan synthase to a specific tyrosine C3-prenylating enzyme.

The tryptophan prenyltransferases FgaPT2 and 7-DMATS (7-dimethylallyl tryptophan synthase) from Aspergillus fumigatus catalyze C(4)- and C(7)-prenylation of the indole ring, respectively. 7-DMATS was found to accept l-tyrosine as substrate as well and converted it to an O-prenylated derivative. An acceptance of l-tyrosine by FgaPT2 was also observed in this study.

A sialic acid binding site in a human picornavirus.

The picornaviruses coxsackievirus A24 variant (CVA24v) and enterovirus 70 (EV70) cause continued outbreaks and pandemics of acute hemorrhagic conjunctivitis (AHC), a highly contagious eye disease against which neither vaccines nor antiviral drugs are currently available. Moreover, these viruses can cause symptoms in the cornea, upper respiratory tract, and neurological impairments such as acute flaccid paralysis. EV70 and CVA24v are both known to use 5-N-acetylneuraminic acid (Neu5Ac) for cell attachment, thus providing a putative link between the glycan receptor specificity and cell tropism and disease.

In vitro reconstitution of a cellular phase-transition process that involves the mRNA decapping machinery.

In eukaryotic cells, components of the 5' to 3' mRNA degradation machinery can undergo a rapid phase transition. The resulting cytoplasmic foci are referred to as processing bodies (P-bodies). The molecular details of the self-aggregation process are, however, largely undetermined.

Catalytic mechanism of stereospecific formation of cis-configured prenylated pyrroloindoline diketopiperazines by indole prenyltransferases.

Indole prenyltransferases AnaPT, CdpC3PT, and CdpNPT are known to catalyze the formation of prenylated pyrroloindoline diketopiperazines from tryptophan-containing cyclic dipeptides in one-step reactions. In this study, we investigated the different stereoselectivities of these enzymes toward all the stereoisomers of cyclo-Trp-Ala and cyclo-Trp-Pro. The stereoselectivities of AnaPT and CdpC3PT mainly depend on the configuration of the tryptophanyl moiety in the substrates, and they usually introduce the prenyl moiety from the opposite sides.

Vinylogous chain branching catalysed by a dedicated polyketide synthase module.

Bacteria use modular polyketide synthases (PKSs) to assemble complex polyketides, many of which are leads for the development of clinical drugs, in particular anti-infectives and anti-tumoral agents. Because these multifarious compounds are notoriously difficult to synthesize, they are usually produced by microbial fermentation. During the past two decades, an impressive body of knowledge on modular PKSs has been gathered that not only provides detailed insight into the biosynthetic pathways but also allows the rational engineering of enzymatic processing lines to yield structural analogues.

Structural basis of the interaction of MbtH-like proteins, putative regulators of nonribosomal peptide biosynthesis, with adenylating enzymes.

The biosynthesis of nonribosomally formed peptides (NRPs), which include important antibiotics such as vancomycin, requires the activation of amino acids through adenylate formation. The biosynthetic gene clusters of NRPs frequently contain genes for small, so-called MbtH-like proteins. Recently, it was discovered that these MbtH-like proteins are required for some of the adenylation reactions in NRP biosynthesis, but the mechanism of their interaction with the adenylating enzymes has remained unknown.

Structure-based engineering increased the catalytic turnover rate of a novel phenazine prenyltransferase.

Prenyltransferases (PTs) catalyze the regioselective transfer of prenyl moieties onto aromatic substrates in biosynthetic pathways of microbial secondary metabolites. Therefore, these enzymes contribute to the chemical diversity of natural products. Prenylation is frequently essential for the pharmacological properties of these metabolites, including their antibiotic and antitumor activities.

Structure and catalytic mechanism of a cyclic dipeptide prenyltransferase with broad substrate promiscuity.

Fungal indole prenyltransferases (PTs) typically act on specific substrates, and they are able to prenylate their target compounds with remarkably high regio- and stereoselectivity. Similar to several indole PTs characterized to date, the cyclic dipeptide N-prenyltransferase (CdpNPT) is able to prenylate a range of diverse substrates, thus exhibiting an unusually broad substrate promiscuity. To define the structural basis for this promiscuity, we have determined crystal structures of unliganded CdpNPT and of a ternary complex of CdpNPT bound to (S)-benzodiazepinedione and thiolodiphosphate.

Facilities for macromolecular crystallography at the Helmholtz-Zentrum Berlin.

Three macromolecular crystallography (MX) beamlines at the Helmholtz-Zentrum Berlin (HZB) are available for the regional, national and international structural biology user community. The state-of-the-art synchrotron beamlines for MX BL14.1, BL14.