Nuclear magnetic resonance (NMR) spectroscopy has become a formidable tool for biochemistry and medicine. Although
J
-coupling carries essential structural information it may also limit the spectral ...resolution. Homonuclear decoupling remains a challenging problem. In this work, we introduce a new approach that uses a specific coupling value as prior knowledge, and the Hankel property of the exponential NMR signal to achieve broadband heteronuclear decoupling using the low-rank method. Our results on synthetic and realistic HMQC spectra demonstrate that the proposed method not only effectively enhances resolution by decoupling, but also maintains sensitivity and suppresses spectral artefacts. The approach can be combined with non-uniform sampling, which means that the resolution can be further improved without any extra acquisition time.
Virtual broad-band homo-decoupling is demonstrated using Hankel property of the NMR signal. The proposed method enhances resolution and maintains sensitivity.
A large-scale optimisation of density functional theory (DFT) conditions for computational NMR structure elucidation has been conducted by systematically screening the DFT functionals and statistical ...models. The extended PyDP4 workflow was tested on a diverse and challenging set of 42 biologically active and stereochemically rich compounds, including highly flexible molecules. MMFF/mPW1PW91/M06-2X in combination with a 2 Gaussian, 1 region statistical model was capable of identifying the correct diastereomer among up to an upper limit of 32 potential diastereomers. Overall a 2-fold reduction in structural uncertainty and a 7-fold reduction in model overconfidence have been achieved. Tools for rapid set-up and analysis of computational and experimental results, as well as for the statistical model generation, have been developed and are provided. All of this should facilitate rapid and reliable computational NMR structure elucidation, which has become a valuable tool to natural product chemists and synthetic chemists alike.
The pneumococcal serine rich repeat protein (PsrP) is displayed on the surface of
Streptococcus pneumoniae
with a suggested role in colonization in the human upper respiratory tract. Full-length PsrP ...is a 4000 residue-long multi-domain protein comprising a positively charged functional binding region (BR) domain for interaction with keratin and extracellular DNA during pneumococcal adhesion and biofilm formation, respectively. The previously determined crystal structure of the BR domain revealed a flat compressed barrel comprising two sides with an extended β-sheet on one side, and another β-sheet that is distorted by loops and β-turns on the other side. Crystallographic B-factors indicated a relatively high mobility of loop regions that were hypothesized to be important for binding. Furthermore, the crystal structure revealed an inter-molecular β-sheet formed between edge strands of two symmetry-related molecules, which could promote bacterial aggregation during biofilm formation. Here we report the near complete
15
N/
13
C/
1
H backbone resonance assignment of the BR domain of PsrP, revealing a secondary structure profile that is almost identical to the X-ray structure. Dynamic
15
N-T
1
, T
2
and NOE data suggest a monomeric and rigid structure of BR with disordered residues only at the N- and C-termini. The presented peak assignment will allow us to identify BR residues that are crucial for ligand binding.
Alphavirus nsP3 proteins contain long, intrinsically disordered, hypervariable domains, HVD, which serve as hubs for interaction with many cellular proteins. Here, we have deciphered the mechanism ...and function of HVD interaction with host factors in alphavirus replication. Using NMR spectroscopy, we show that CHIKV HVD contains two SH3 domain-binding sites. Using an innovative chemical shift perturbation signature approach, we demonstrate that CD2AP interaction with HVD is mediated by its SH3-A and SH3–C domains, and this leaves the SH3–B domain available for interaction with other cellular factor(s). This cooperative interaction with two SH3 domains increases binding affinity to CD2AP and possibly induces long-range allosteric effects in HVD. Our data demonstrate that BIN1, CD2AP and SH3KBP1 play redundant roles in initiation of CHIKV replication. Point mutations in both CHIKV HVD binding sites abolish its interaction with all three proteins, CD2AP, BIN1 and SH3KBP1. This results in strong inhibition of viral replication initiation.
•Hypervariable domain of CHIKV nsP3 (HVD) contains two SH3 domain-binding motifs.•SH3-A and SH3–C domains of CD2AP cooperatively mediate its interaction with CHIKV HVD.•Chemical shift perturbation signature can be applied for identification of interacting domains in multidomain proteins.•Mutations in both motifs of CHIKV HVD inhibit initiation of virus replication.•CD2AP, SH3KBP1 and BIN1 play redundant roles in CHIKV replication.
The nonuniform sampling (NUS) is a powerful approach to enable fast acquisition but requires sophisticated reconstruction algorithms. Faithful reconstruction from partially sampled exponentials is ...highly expected in general signal processing and many applications. Deep learning (DL) has shown astonishing potential in this field, but many existing problems, such as lack of robustness and explainability, greatly limit its applications. In this work, by combining the merits of the sparse model-based optimization method and data-driven DL, we propose a DL architecture for spectra reconstruction from undersampled data, called MoDern. It follows the iterative reconstruction in solving a sparse model to build the neural network, and we elaborately design a learnable soft-thresholding to adaptively eliminate the spectrum artifacts introduced by undersampling. Extensive results on both synthetic and biological data show that MoDern enables more robust, high-fidelity, and ultrafast reconstruction than the state-of-the-art methods. Remarkably, MoDern has a small number of network parameters and is trained on solely synthetic data while generalizing well to biological data in various scenarios. Furthermore, we extend it to an open-access and easy-to-use cloud computing platform (XCloud-MoDern), contributing a promising strategy for further development of biological applications.
Mucosa-associated lymphoid tissue protein 1 (MALT1) plays a key role in adaptive immune responses by modulating specific intracellular signalling pathways that control the development and ...proliferation of both T and B cells. Dysfunction of these pathways is coupled to the progress of highly aggressive lymphoma as well as to potential development of an array of different immune disorders. In contrast to other signalling mediators, MALT1 is not only activated through the formation of the CBM complex together with the proteins CARMA1 and Bcl10, but also by acting as a protease that cleaves multiple substrates to promote lymphocyte proliferation and survival via the NF-kappa B signalling pathway. Herein, we present the partial H-1, C-13 Ile/Val/Leu-Methyl resonance assignment of the monomeric apo form of the paracaspase-IgL(3) domain of human MALT1. Our results provide a solid ground for future elucidation of both the three-dimensional structure and the dynamics of MALT1, key for adequate development of inhibitors, and a thorough molecular understanding of its function(s).
The serotype II Dengue (DENV 2) virus is the most prevalent of all four known serotypes. Herein, we present nearly complete H-1, N-15, and C-13 backbone and H-1, C-13 isoleucine, valine, and leucine ...methyl resonance assignment of the apo S135A catalytically inactive variant of the DENV 2 protease enzyme folded as a tandem formed between the serine protease domain NS3pro and the cofactor NS2B, as well as the secondary structure prediction of this complex based on the assigned chemical shifts using the TALOS-N software. Our results provide a solid ground for future elucidation of the structure and dynamic of the apo NS3pro/NS2B complex, key for adequate development of inhibitors, and a thorough molecular understanding of their function(s).
Mucosa-associated lymphoid tissue protein 1 (MALT1) plays a key role in adaptive immune responses by modulating specific intracellular signalling pathways that control the development and ...proliferation of both T and B cells. Dysfunction of these pathways is coupled to the progress of highly aggressive lymphoma as well as to potential development of an array of different immune disorders. In contrast to other signalling mediators, MALT1 is not only activated through the formation of the CBM complex together with the proteins CARMA1 and Bcl10, but also by acting as a protease that cleaves multiple substrates to promote lymphocyte proliferation and survival via the NF-κB signalling pathway. Herein, we present the partial
1
H,
13
C Ile/Val/Leu-Methyl resonance assignment of the monomeric apo form of the paracaspase-IgL
3
domain of human MALT1. Our results provide a solid ground for future elucidation of both the three-dimensional structure and the dynamics of MALT1, key for adequate development of inhibitors, and a thorough molecular understanding of its function(s).
The serotype II Dengue (DENV 2) virus is the most prevalent of all four known serotypes. Herein, we present nearly complete
1
H,
15
N, and
13
C backbone and
1
H,
13
C isoleucine, valine, and leucine ...methyl resonance assignment of the apo S135A catalytically inactive variant of the DENV 2 protease enzyme folded as a tandem formed between the serine protease domain NS3pro and the cofactor NS2B, as well as the secondary structure prediction of this complex based on the assigned chemical shifts using the TALOS-N software. Our results provide a solid ground for future elucidation of the structure and dynamic of the apo NS3pro/NS2B complex, key for adequate development of inhibitors, and a thorough molecular understanding of their function(s).
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