Learned trustworthiness does not have the same influence on implicit responses measured via fast periodic visual stimulation as face trustworthiness.

Past research has demonstrated that it is possible to detect implicit responses to face trustworthiness using fast periodic visual stimulation (FPVS). Because people readily retrieve affective associations with faces, the current study investigated whether learned trustworthiness would yield similar responses to face trustworthiness as measured via FPVS. After learning to associate faces with untrustworthy or trustworthy behaviors, participants completed three separate tasks while electroencephalography (EEG) was recorded. In each of these tasks, participants viewed oddball sequences of faces where a single base face was presented repeatedly at a rate of 6 Hz and oddball faces with different identities were presented every fifth face (6 Hz/5 = 1.2 Hz). Providing evidence of learning, the oddball response at 1.2 Hz and its harmonics was stronger for the learned faces compared to novel faces over bilateral occipitotemporal cortex and beyond. In addition, reproducing previous findings with face trustworthiness, we observed a stronger response at 1.2 Hz and its harmonics for sequences with less trustworthy-looking versus trustworthy-looking oddball faces over bilateral occipitotemporal cortex and other sites. However, contrary to our predictions, we did not observe a significant influence of learned trustworthiness on the oddball response. These data indicate that impressions based on learning are treated differently than impressions based on appearance, and they raise questions about the types of design and stimuli that yield responses that are measurable via FPVS.

The association between quality of life and subjective wellbeing among older adults based on canonical correlation analysis.

Introduction: The study explored the relationship between subjective well-being and the quality of life among older adults. It highlights the importance of understanding how these factors are interconnected in the context of an aging population. Methods: Descriptive statistics were used to analyze the scores of general demographic characteristics, subjective wellbeing and quality of life. Simple correlation analysis and canonical correlation analysis were employed to analyze the relationship between subjective wellbeing and quality of life among older adults. Results: Data from 892 older adults were collected. Canonical correlation analysis revealed four pairs of canonical variables, with the first four pairs of canonical correlation coefficients all being statistically significant (0.695, 0.179, 0.147, 0.121) (p < 0.05), and the first pair of canonical variables explaining 93.03% of the information content. From the canonical loading coefficients, Vitality and mental health contributed the most to the quality of life (U1) canonical variable. The canonical variable V1, which corresponded to subjective wellbeing, was reflected by a combination of positive affect, negative affect, positive experience and negative experience. X1 (physical functioning), X2 (role-physical), X3 (bodily pain), X4 (general health), X5 (vitality), X6 (social functioning), X7 (role-emotional) and X8 (mental health) were positively correlated with Y1 (positive affect) and Y3 (positive experience), negatively correlated with Y2 (negative affect) and Y4 (negative experience). Cross-loadings revealed that physical functioning, bodily pain, general health, vitality, social functioning and mental health were the main factors reflecting the subjective wellbeing of older adults. Discussion: As quality of life among older adults was highly correlated with subjective wellbeing, appropriate measures should be taken to account for individual characteristics of older adults, and various factors should be integrated to improve their subjective wellbeing.

The Association of Perceived Neighbourhood Environment and Subjective Wellbeing in Migrant Older Adults: A Cross-Sectional Study Using Canonical Correlation Analysis.

Existing studies often focus on the impact of the neighbourhood environment on the subjective wellbeing (SWB) of the residents. Very few studies explore the impacts of the neighbourhood environment on migrant older adults. This study was conducted to investigate the correlations between perceived neighbourhood environment (PNE) and SWB among migrant older adults. A cross-sectional design was adopted. Data were collected from 470 migrant older adults in Dongguan, China. General characteristics, levels of SWB, and PNE were collected via a self-reported questionnaire. Canonical correlation analysis was performed to evaluate the relationship between PNE and SWB. These variables accounted for 44.1% and 53.0% of the variance, respectively. Neighbourhood relations, neighbourhood trust, and similar values in social cohesion made the most important contributions correlated with positive emotion and positive experience. A link between SWB and walkable neighbourhoods characterized by opportunities and facilities for physical activities with other people walking or exercising in their community, is positively associated with positive emotions. Our findings suggest that migrant older adults have a good walkable environment and social cohesion in neighbourhoods positively correlated with their subjective wellbeing. Therefore, the government should provide a more robust activity space for neighbourhoods and build an inclusive community for older adults.

The lipid linked oligosaccharide polymerase Wzy and its regulating co-polymerase, Wzz, from enterobacterial common antigen biosynthesis form a complex.

The enterobacterial common antigen (ECA) is a carbohydrate polymer that is associated with the cell envelope in the Enterobacteriaceae. ECA contains a repeating trisaccharide which is polymerized by WzyE, a member of the Wzy membrane protein polymerase superfamily. WzyE activity is regulated by a membrane protein polysaccharide co-polymerase, WzzE. Förster resonance energy transfer experiments demonstrate that WzyE and WzzE from Pectobacterium atrosepticum form a complex in vivo, and immunoblotting and cryo-electron microscopy (cryo-EM) analysis confirm a defined stoichiometry of approximately eight WzzE to one WzyE. Low-resolution cryo-EM reconstructions of the complex, aided by an antibody recognizing the C-terminus of WzyE, reveals WzyE sits in the central membrane lumen formed by the octameric arrangement of the transmembrane helices of WzzE. The pairing of Wzy and Wzz is found in polymerization systems for other bacterial polymers, including lipopolysaccharide O-antigens and capsular polysaccharides. The data provide new structural insight into a conserved mechanism for regulating polysaccharide chain length in bacteria.

NOX4-derived ROS-induced overexpression of FOXM1 regulates aerobic glycolysis in glioblastoma.

BACKGROUND: Increased expression of the transcription factor Forkhead box M1 (FOXM1) has been reported to play an important role in the progression and development of multiple tumors, but the molecular mechanisms that regulate FOXM1 expression remain unknown, and the role of FOXM1 in aerobic glycolysis is still not clear. METHODS: The expression of FOXM1 and NADPH oxidase 4 (NOX4) in normal brain tissues and glioma was detected in data from the TCGA database and in our specimens. The effect of NOX4 on the expression of FOXM1 was determined by Western blot, qPCR, reactive oxygen species (ROS) production assays, and luciferase assays. The functions of NOX4 and FOXM1 in aerobic glycolysis in glioblastoma cells were determined by a series of experiments, such as Western blot, extracellular acidification rate (ECAR), lactate production, and intracellular ATP level assays. A xenograft mouse model was established to test our findings in vivo. RESULTS: The expression of FOXM1 and NOX4 was increased in glioma specimens compared with normal brain tissues and correlated with poor clinical outcomes. Aberrant mitochondrial reactive oxygen species (ROS) generation of NOX4 induced FOXM1 expression. Mechanistic studies demonstrated that NOX4-derived MitoROS exert their regulatory role on FOXM1 by mediating hypoxia-inducible factor 1α (HIF-1α) stabilization. Further research showed that NOX4-derived MitoROS-induced HIF-1α directly activates the transcription of FOXM1 and results in increased FOXM1 expression. Overexpression of NOX4 or FOXM1 promoted aerobic glycolysis, whereas knockdown of NOX4 or FOXM1 significantly suppressed aerobic glycolysis, in glioblastoma cells. NOX4-induced aerobic glycolysis was dependent on elevated FOXM1 expression, as FOXM1 knockdown abolished NOX4-induced aerobic glycolysis in glioblastoma cells both in vitro and in vivo. CONCLUSION: Increased expression of FOXM1 induced by NOX4-derived MitoROS plays a pivotal role in aerobic glycolysis, and our findings suggest that inhibition of NOX4-FOXM1 signaling may present a potential therapeutic target for glioblastoma treatment.

Uncovering the chemistry of C-C bond formation in C-nucleoside biosynthesis: crystal structure of a C-glycoside synthase/PRPP complex.

The enzyme ForT catalyzes C-C bond formation between 5'-phosphoribosyl-1'-pyrophosphate (PRPP) and 4-amino-1H-pyrazole-3,5-dicarboxylate to make a key intermediate in the biosynthesis of formycin A 5'-phosphate by Streptomyces kaniharaensis. We report the 2.5 Å resolution structure of the ForT/PRPP complex and locate active site residues critical for PRPP recognition and catalysis.

PMP-diketopiperazine adducts form at the active site of a PLP dependent enzyme involved in formycin biosynthesis.

ForI is a PLP-dependent enzyme from the biosynthetic pathway of the C-nucleoside antibiotic formycin. Cycloserine is thought to inhibit PLP-dependent enzymes by irreversibly forming a PMP-isoxazole. We now report that ForI forms novel PMP-diketopiperazine derivatives following incubation with both d and l cycloserine. This unexpected result suggests chemical diversity in the chemistry of cycloserine inhibition.

Structural basis for enzymatic photocatalysis in chlorophyll biosynthesis.

The enzyme protochlorophyllide oxidoreductase (POR) catalyses a light-dependent step in chlorophyll biosynthesis that is essential to photosynthesis and, ultimately, all life on Earth1-3. POR, which is one of three known light-dependent enzymes4,5, catalyses reduction of the photosensitizer and substrate protochlorophyllide to form the pigment chlorophyllide. Despite its biological importance, the structural basis for POR photocatalysis has remained unknown. Here we report crystal structures of cyanobacterial PORs from Thermosynechococcus elongatus and Synechocystis sp. in their free forms, and in complex with the nicotinamide coenzyme. Our structural models and simulations of the ternary protochlorophyllide-NADPH-POR complex identify multiple interactions in the POR active site that are important for protochlorophyllide binding, photosensitization and photochemical conversion to chlorophyllide. We demonstrate the importance of active-site architecture and protochlorophyllide structure in driving POR photochemistry in experiments using POR variants and protochlorophyllide analogues. These studies reveal how the POR active site facilitates light-driven reduction of protochlorophyllide by localized hydride transfer from NADPH and long-range proton transfer along structurally defined proton-transfer pathways.

High levels of circulating endothelial progenitor cells in patients with diabetic retinopathy are positively associated with ARHGAP22 expression.

Diabetic retinopathy (DR) is a common microvascular complication of diabetes. Circulating endothelial progenitor cells (EPCs) are derived from bone marrow and are characterized by pathological retinal neovascularization. Rho GTPase Activating Protein 22 (ARHGAP22) is a DR susceptibility gene that interacts with its downstream regulatory protein ras-related C3 botulinum toxin substrate 1 (Rac1), to assist in endothelial cell angiogenesis and increasing capillary permeability. The aim of this study was to elucidate the relationship between ARHGAP22 expression and EPC levels in type 2 diabetes (T2D) patients with DR. Fifty T2D patients with DR were recruited. Circulating EPCs were characterized as CD31+/vascular endothelial growth factor-2+/CD45dim/CD133+ and were quantified using triple staining flow cytometry. Real-time polymerase chain reaction tests were used to quantify ARHGAP22 expression. We found that T2D patients with proliferative DR had significantly lower EPC levels than those with non-proliferative DR (P = 0.028). T2D patients with EPC levels above the median value (> 4 cells/105 events) had higher levels of ARHGAP22 expression (P = 0.002). EPC levels were positively correlated with ARHGAP22 expression (r = 0.364, P = 0.009). Among T2D patients with DR, a higher expression of ARHGAP22 was associated with higher levels of EPCs. ARHGAP22 may be involved in the mobilization or active circulation of EPCs, thus contributing to neovascularization during DR development.

The rhizoferrin biosynthetic gene in the fungal pathogen Rhizopus delemar is a novel member of the NIS gene family.

Iron is essential for growth and in low iron environments such as serum many bacteria and fungi secrete ferric iron-chelating molecules called siderophores. All fungi produce hydroxamate siderophores with the exception of Mucorales fungi, which secrete rhizoferrin, a polycarboxylate siderophore. Here we investigated the biosynthesis of rhizoferrin by the opportunistic human pathogen, Rhizopus delemar. We searched the genome of R. delemar 99-880 for a homologue of the bacterial NRPS-independent siderophore (NIS) protein, SfnaD, that is involved in biosynthesis of staphyloferrin A in Staphylococcus aureus. A protein was identified in R. delemar with 22% identity and 37% similarity with SfnaD, containing an N-terminal IucA/IucC family domain, and a C-terminal conserved ferric iron reductase FhuF-like transporter domain. Expression of the putative fungal rhizoferrin synthetase (rfs) gene was repressed by iron. The rfs gene was cloned and expressed in E.coli and siderophore biosynthesis from citrate and diaminobutane was confirmed using high resolution LC-MS. Substrate specificity was investigated showing that Rfs produced AMP when oxaloacetic acid, tricarballylic acid, ornithine, hydroxylamine, diaminopentane and diaminopropane were employed as substrates. Based on the production of AMP and the presence of a mono-substituted rhizoferrin, we suggest that Rfs is a member of the superfamily of adenylating enzymes. We used site-directed mutagenesis to mutate selected conserved residues predicted to be in the Rfs active site. These studies revealed that H484 is essential for Rfs activity and L544 may play a role in amine recognition by the enzyme. This study on Rfs is the first characterization of a fungal NIS enzyme. Future work will determine if rhizoferrin biosynthesis is required for virulence in Mucorales fungi.

Kinetics and Structure of a Cold-Adapted Hetero-Octameric ATP Phosphoribosyltransferase.

Adenosine 5'-triphosphate phosphoribosyltransferase (ATPPRT) catalyzes the first step in histidine biosynthesis, the condensation of ATP and 5-phospho-α-d-ribosyl-1-pyrophosphate to generate N1-(5-phospho-ß-d-ribosyl)-ATP and inorganic pyrophosphate. The enzyme is allosterically inhibited by histidine. Two forms of ATPPRT, encoded by the hisG gene, exist in nature, depending on the species. The long form, HisGL, is a single polypeptide chain with catalytic and regulatory domains. The short form, HisGS, lacks a regulatory domain and cannot bind histidine. HisGS instead is found in complex with a regulatory protein, HisZ, constituting the ATPPRT holoenzyme. HisZ triggers HisGS catalytic activity while rendering it sensitive to allosteric inhibition by histidine. Until recently, HisGS was thought to be catalytically inactive without HisZ. Here, recombinant HisGS and HisZ from the psychrophilic bacterium Psychrobacter arcticus were independently overexpressed and purified. The crystal structure of P. arcticus ATPPRT was determined at 2.34 Å resolution, revealing an equimolar HisGS-HisZ hetero-octamer. Steady-state kinetics indicate that both the ATPPRT holoenzyme and HisGS are catalytically active. Surprisingly, HisZ confers only a modest 2-4-fold increase in kcat. Reaction profiles for both enzymes cannot be distinguished by 31P nuclear magnetic resonance, indicating that the same reaction is catalyzed. The temperature dependence of kcat shows deviation from Arrhenius behavior at 308 K with the holoenzyme. Interestingly, such deviation is detected only at 313 K with HisGS. Thermal denaturation by CD spectroscopy resulted in Tm's of 312 and 316 K for HisZ and HisGS, respectively, suggesting that HisZ renders the ATPPRT complex more thermolabile. This is the first characterization of a psychrophilic ATPPRT.

Pironetin reacts covalently with cysteine-316 of α-tubulin to destabilize microtubule.

Molecules that alter the normal dynamics of microtubule assembly and disassembly include many anticancer drugs in clinical use. So far all such therapeutics target ß-tubulin, and structural biology has explained the basis of their action and permitted design of new drugs. However, by shifting the profile of ß-tubulin isoforms, cancer cells become resistant to treatment. Compounds that bind to α-tubulin are less well characterized and unexploited. The natural product pironetin is known to bind to α-tubulin and is a potent inhibitor of microtubule polymerization. Previous reports had identified that pironetin reacts with lysine-352 residue however analogues designed on this model had much lower potency, which was difficult to explain, hindering further development. We report crystallographic and mass spectrometric data that reveal that pironetin forms a covalent bond to cysteine-316 in α-tubulin via a Michael addition reaction. These data provide a basis for the rational design of α-tubulin targeting chemotherapeutics.

Multiple nucleic acid cleavage modes in divergent type III CRISPR systems.

CRISPR-Cas is an RNA-guided adaptive immune system that protects bacteria and archaea from invading nucleic acids. Type III systems (Cmr, Csm) have been shown to cleave RNA targets in vitro and some are capable of transcription-dependent DNA targeting. The crenarchaeon Sulfolobus solfataricus has two divergent subtypes of the type III system (Sso-IIID and a Cmr7-containing variant of Sso-IIIB). Here, we report that both the Sso-IIID and Sso-IIIB complexes cleave cognate RNA targets with a ruler mechanism and 6 or 12 nt spacing that relates to the organization of the Cas7 backbone. This backbone-mediated cleavage activity thus appears universal for the type III systems. The Sso-IIIB complex is also known to possess a distinct 'UA' cleavage mode. The predominant activity observed in vitro depends on the relative molar concentration of protein and target RNA. The Sso-IIID complex can cleave plasmid DNA targets in vitro, generating linear DNA products with an activity that is dependent on both the cyclase and HD nuclease domains of the Cas10 subunit, suggesting a role for both nuclease active sites in the degradation of double-stranded DNA targets.

Unraveling the specific regulation of the central pathway for anaerobic degradation of 3-methylbenzoate.

The mbd cluster encodes the anaerobic degradation of 3-methylbenzoate in the ß-proteobacterium Azoarcus sp. CIB. The specific transcriptional regulation circuit that controls the expression of the mbd genes was investigated. The PO, PB 1, and P3 R promoters responsible for the expression of the mbd genes, their cognate MbdR transcriptional repressor, as well as the MbdR operator regions (ATACN10GTAT) have been characterized. The three-dimensional structure of MbdR has been solved revealing a conformation similar to that of other TetR family transcriptional regulators. The first intermediate of the catabolic pathway, i.e. 3-methylbenzoyl-CoA, was shown to act as the inducer molecule. An additional MbdR-dependent promoter, PA, which contributes to the expression of the CoA ligase that activates 3-methylbenzoate to 3-methylbenzoyl-CoA, was shown to be necessary for an efficient induction of the mbd genes. Our results suggest that the mbd cluster recruited a regulatory system based on the MbdR regulator and its target promoters to evolve a distinct central catabolic pathway that is only expressed for the anaerobic degradation of aromatic compounds that generate 3-methylbenzoyl-CoA as the central metabolite. All these results highlight the importance of the regulatory systems in the evolution and adaptation of bacteria to the anaerobic degradation of aromatic compounds.

A coiled-coil domain acts as a molecular ruler to regulate O-antigen chain length in lipopolysaccharide.

Long-chain bacterial polysaccharides have important roles in pathogenicity. In Escherichia coli O9a, a model for ABC transporter-dependent polysaccharide assembly, a large extracellular carbohydrate with a narrow size distribution is polymerized from monosaccharides by a complex of two proteins, WbdA (polymerase) and WbdD (terminating protein). Combining crystallography and small-angle X-ray scattering, we found that the C-terminal domain of WbdD contains an extended coiled-coil that physically separates WbdA from the catalytic domain of WbdD. The effects of insertions and deletions in the coiled-coil region were analyzed in vivo, revealing that polymer size is controlled by varying the length of the coiled-coil domain. Thus, the coiled-coil domain of WbdD functions as a molecular ruler that, along with WbdA:WbdD stoichiometry, controls the chain length of a model bacterial polysaccharide.

An efficient method for the in vitro production of azol(in)e-based cyclic peptides.

Heterocycle-containing cyclic peptides are promising scaffolds for the pharmaceutical industry but their chemical synthesis is very challenging. A new universal method has been devised to prepare these compounds by using a set of engineered marine-derived enzymes and substrates obtained from a family of ribosomally produced and post-translationally modified peptides called the cyanobactins. The substrate precursor peptide is engineered to have a non-native protease cleavage site that can be rapidly cleaved. The other enzymes used are heterocyclases that convert Cys or Cys/Ser/Thr into their corresponding azolines. A macrocycle is formed using a macrocyclase enzyme, followed by oxidation of the azolines to azoles with a specific oxidase. The work is exemplified by the production of 17 macrocycles containing 6-9 residues representing 11 out of the 20 canonical amino acids.

Structure of the archaeal Cascade subunit Csa5: relating the small subunits of CRISPR effector complexes.

The Cascade complex for CRISPR-mediated antiviral immunity uses CRISPR RNA (crRNA) to target invading DNA species from mobile elements such as viruses, leading to their destruction. The core of the Cascade effector complex consists of the Cas5 and Cas7 subunits, which are widely conserved in prokaryotes. Cas7 binds crRNA and forms the helical backbone of Cascade. Many archaea encode a version of the Cascade complex (denoted Type I-A) that includes a Csa5 (or small) subunit, which interacts weakly with the core proteins. Here, we report the crystal structure of the Csa5 protein from Sulfolobus solfataricus. Csa5 comprises a conserved α-helical domain with a small insertion consisting of a weakly conserved ß-strand domain. In the crystal, the Csa5 monomers have multimerized into infinite helical threads. At each interface is a strictly conserved intersubunit salt bridge, deletion of which disrupts multimerization. Structural analysis indicates a shared evolutionary history among the small subunits of the CRISPR effector complexes. The same α-helical domain is found in the C-terminal domain of Cse2 (from Type I-E Cascade), while the N-terminal domain of Cse2 is found in Cmr5 of the CMR (Type III-B) effector complex. As Cmr5 shares no match with Csa5, two possibilities present themselves: selective domain loss from an ancestral Cse2 to create two new subfamilies or domain fusion of two separate families to create a new Cse2 family. A definitive answer awaits structural studies of further small subunits from other CRISPR effector complexes.

Genetic structure of rice black-streaked dwarf virus populations in China.

Rice black-streaked dwarf virus (RBSDV) is a double-stranded RNA (dsRNA) virus belonging to the genus Fijivirus in the family Reoviridae. The genome of RBSDV consists of ten dsRNA segments. Although RBSDV has caused significant economic losses to rice and maize production in the past few years in China, its molecular diversity and evolution remain largely unknown. To elucidate the factor(s) underlying the evolution of RBSDV, we determined segment 8 (S8; carrying ORF8 encoding the minor core capsid protein) sequences of 101 samples and segment 10 (S10; carrying ORF10 encoding the major capsid protein) sequences of 103 samples. The results show that both ORF8 and ORF10 are under negative selection. The S8 of three isolates and S10 of two isolates are recombinants. The RBSDV population in China can be classified into three groups according to S8 sequences or into two groups according to S10 sequences, irrespective of host or geographical origin. Of the RBSDV isolates with both S8 and S10 sequences available, 17 are between-group reassortants and 30 are between-subgroup reassortants. The RBSDV subpopulations from different geographical regions and hosts show frequent gene flow within or between subpopulations. The RBSDV population from maize is in a state of expansion. In this study, no new emergent population was detected. Taken together, the results indicate that, in addition to recombination and negative selection, reassortment and gene flow are important factors that drive evolution of RBSDV in China.

Structure of a dimeric crenarchaeal Cas6 enzyme with an atypical active site for CRISPR RNA processing.

The competition between viruses and hosts is played out in all branches of life. Many prokaryotes have an adaptive immune system termed 'CRISPR' (clustered regularly interspaced short palindromic repeats) which is based on the capture of short pieces of viral DNA. The captured DNA is integrated into the genomic DNA of the organism flanked by direct repeats, transcribed and processed to generate crRNA (CRISPR RNA) that is loaded into a variety of effector complexes. These complexes carry out sequence-specific detection and destruction of invading mobile genetic elements. In the present paper, we report the structure and activity of a Cas6 (CRISPR-associated 6) enzyme (Sso1437) from Sulfolobus solfataricus responsible for the generation of unit-length crRNA species. The crystal structure reveals an unusual dimeric organization that is important for the enzyme's activity. In addition, the active site lacks the canonical catalytic histidine residue that has been viewed as an essential feature of the Cas6 family. Although several residues contribute towards catalysis, none is absolutely essential. Coupled with the very low catalytic rate constants of the Cas6 family and the plasticity of the active site, this suggests that the crRNA recognition and chaperone-like activities of the Cas6 family should be considered as equal to or even more important than their role as traditional enzymes.

The AEROPATH project targeting Pseudomonas aeruginosa: crystallographic studies for assessment of potential targets in early-stage drug discovery.

Bacterial infections are increasingly difficult to treat owing to the spread of antibiotic resistance. A major concern is Gram-negative bacteria, for which the discovery of new antimicrobial drugs has been particularly scarce. In an effort to accelerate early steps in drug discovery, the EU-funded AEROPATH project aims to identify novel targets in the opportunistic pathogen Pseudomonas aeruginosa by applying a multidisciplinary approach encompassing target validation, structural characterization, assay development and hit identification from small-molecule libraries. Here, the strategies used for target selection are described and progress in protein production and structure analysis is reported. Of the 102 selected targets, 84 could be produced in soluble form and the de novo structures of 39 proteins have been determined. The crystal structures of eight of these targets, ranging from hypothetical unknown proteins to metabolic enzymes from different functional classes (PA1645, PA1648, PA2169, PA3770, PA4098, PA4485, PA4992 and PA5259), are reported here. The structural information is expected to provide a firm basis for the improvement of hit compounds identified from fragment-based and high-throughput screening campaigns.