pFind Studio: a computational solution for mass spectrometry-based proteomics



2024




Ontogeny, not prey availability, underlies allopatric venom variability in insular and mainland populations of Vipera ammodytes
Journal of proteomics2024. Laku{\v{s}}i{\'c}, Margareta et al. CIBIO, Centro de Investigao em Biodiversidade e Recursos Genticos, InBIO Laboratrio Associado, Campus de Vairo, Universidade do Porto, 4485-661 Vairo, Portugal
ABSTRACT:Allopatric populations living under distinct ecological conditions are excellent systems to infer factors underlying intraspecific venom variation. The venom composition of two populations of Vipera ammodytes, , insular with a diet based on ectotherms and mainland with a diet based on ectotherms and endotherms, was compared considering the sex and age of individuals. Ten toxin families, dominated by PLA2, 2 , svMP, svSP, and DI, were identified through a bottom-up approach. The venom profiles of adult females and males were similar. Results from 58 individual SDS-PAGE profiles and venom pool analysis revealed significant differences between juveniles compared to subadults and adults. Two venom phenotypes were identified: a juvenile svMP-dominated and KUNlacking phenotype and an adult PLA2/svMP-balanced 2 /svMP-balanced and KUN-containing phenotype. Despite differences in prey availability (and, therefore, diet) between populations, no significant differences in venom composition were found. As the populations are geographically isolated, the lack of venom diversification could be explained by insufficient time for natural selection and/or genetic drift to act on the venom composition of island vipers. However, substantial differences in proteomes were observed when compared to venoms from geographically distant populations inhabiting different conditions. These findings highlight the need to consider ecological and evolutionary processes when studying venom variability. Significance: This study provides the first comprehensive analysis of the venom composition of two allopatric populations of Vipera ammodytes, , living under similar abiotic (climate) but distinct biotic (prey availability) conditions. The ontogenetic changes in venom composition, coupled with the lack of differences between sex and between populations, shed light on the main determinants of venom evolution in this medically important snake. Seven new proteomes may facilitate future comparative studies of snake venom evolution. This study highlights the importance of considering ecological and evolutionary factors to understand snake venom variation.
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Venom variation among the three subspecies of the north African mountain viper Vipera monticola Saint Girons 1953
Biochimie2024. Damm, Maik et al. CIBIO, Centro de Investigao em Biodiversidade e Recursos Genticos, InBIO Laboratrio Associado, Campus de Vairo, Universidade do Porto, 4485-661, Vairo, Portugal
ABSTRACT:The North African mountain viper (Vipera monticola) is a medically relevant venomous snake distributed in Morocco, Algeria, and Tunisia. Three subspecies of V.monticola, exhibiting differences in morphotypes and dietary regimes, are currently recognised: V.m. monticola, V.m. atlantica, and V.m. saintgironsi. Through the application of snake venomics, we analysed the venoms of specimens of Moroccan origin belonging to each of the three subspecies. Snake venom metalloproteinases (svMP), snake venom serine proteases (svSP), C-type lectin and C-type lectin-related proteins (CTL), and phospholipases A2 (PLA2) were predominant, with PLA2 being the most abundant toxin family overall. Disintegrins (DI) and cysteine-rich secretory proteins (CRISP) were exclusive to V.m. monticola and V.m. atlantica, while l-amino-acid oxidases (LAAO) were only found in V.m. saintgironsi. The differences detected in the venom profiles, as well as in presence/absence and relative abundances of toxin families, indicate the occurrence of intraspecific venom variation within V.monticola. The identified patterns of venom similarity between subspecies seem to align more with their phylogenetic relationships than with the reported differences in their feeding habits.
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ZASP: A Highly Compatible and Sensitive ZnCl2 Precipitation-Assisted Sample Preparation Method for Proteomic Analysis
Molecular & Cellular Proteomics2024. Shao, Xianfeng et al. State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
ABSTRACT:Universal sample preparation for proteomic analysis that enables unbiased protein manipulation, flexible reagent use, and low protein loss is required to ensure the highest sensitivity of downstream liquid chromatography-mass spectrometry (LC-MS) analysis. To address these needs, we developed a ZnCl2 2 precipitation-assisted sample preparation method (ZASP) that depletes harsh detergents and impurities in protein solutions prior to trypsin digestion via 10 min of ZnCl2 2 and methanol-induced protein precipitation at room temperature (RT). ZASP can remove trypsin digestion and LC-MS incompatible detergents such as SDS, Triton X-100, and urea at high concentrations in solution and unbiasedly recover proteins independent of the amount of protein input. We demonstrated the sensitivity and reproducibility of ZASP in an analysis of samples with 1 mu g to 1000 mu g of proteins. Compared to commonly used sample preparation methods such as SDC-based in-solution digestion, acetone precipitation, FASP, and SP3, ZASP has proven to be an efficient approach. Here, we present ZASP, a practical, robust, and cost-effective proteomic sample preparation method that can be applied to profile different types of samples.
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Structural insights into the cross-exon to cross-intron spliceosome switch
Nature2024. Zhang, Zhenwei et al. Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Gttingen, Germany
ABSTRACT:Early spliceosome assembly can occur through an intron-defined pathway, whereby U1 and U2 small nuclear ribonucleoprotein particles (snRNPs) assemble across the intron1. Alternatively, it can occur through an exon-defined pathway2-5, whereby U2 binds the branch site located upstream of the defined exon and U1 snRNP interacts with the 5'splice site located directly downstream of it. The U4/U6.U5 tri-snRNP subsequently binds to produce a cross-intron (CI) or cross-exon (CE) pre-B complex, which is then converted to the spliceosomal Bcomplex6,7. Exon definition promotes the splicing of upstream introns2,8,9 and plays a key part in alternative splicing regulation10-16. However, the three-dimensional structure of exon-defined spliceosomal complexes and the molecular mechanism of the conversion from a CE-organized to a CI-organized spliceosome, a pre-requisite for splicing catalysis, remain poorly understood. Here cryo-electron microscopy analyses of human CE pre-Bcomplex and B-like complexes reveal extensive structural similarities with their CI counterparts. The results indicate that the CE and CI spliceosome assembly pathways converge already at the pre-B stage. Add-back experiments using purified CE pre-B complexes, coupled with cryo-electron microscopy, elucidate the order of the extensive remodelling events that accompany the formation of Bcomplexes and B-like complexes. The molecular triggers and roles of B-specific proteins in these rearrangements are also identified. We show that CE pre-B complexes can productively bind in trans to a U1 snRNP-bound 5'splice site. Together, our studies provide new mechanistic insights into the CE to CI switch during spliceosome assembly and its effect on pre-mRNA splice site pairing at this stage.
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Cell fixation improves performance of in situ crosslinking mass spectrometry while preserving cellular ultrastructure
Nature Communications2024. Michael, Andrew RM et al. Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, T2N-4N1, Canada
ABSTRACT:
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The Molecular Architecture of the Nuclear Basket
Cell2024. Singh, Digvijay et al. 1School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA.
ABSTRACT:
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Dynamic molecular architecture and substrate recruitment of cullin3--RING E3 ligase CRL3KBTBD2
Nature Structural & Molecular Biology2024. Hu, Yuxia et al. Molecular Genetics II, Center of Medical Biotechnology, University of Duisburg-Essen, Universittsstrae 2-5, 45141, Essen, Germany
ABSTRACT:Phosphatidylinositol 3-kinase alpha, a heterodimer of catalytic p110 alpha and one of five regulatory subunits, mediates insulin- and insulin like growth factor-signaling and, frequently, oncogenesis. Cellular levels of the regulatory p85 alpha subunit are tightly controlled by regulated proteasomal degradation. In adipose tissue and growth plates, failure of K48-linked p85 alpha ubiquitination causes diabetes, lipodystrophy and dwarfism in mice, as in humans with SHORT syndrome. Here we elucidated the structures of the key ubiquitin ligase complexes regulating p85 alpha availability. Specificity is provided by the substrate receptor KBTBD2, which recruits p85 alpha to the cullin3-RING E3 ubiquitin ligase (CRL3). CRL3(KBTBD2) forms multimers, which disassemble into dimers upon substrate binding (CRL3(KBTBD2)-p85 alpha) and/or neddylation by the activator NEDD8 (CRL3(KBTBD2)similar to N8), leading to p85 alpha ubiquitination and degradation. Deactivation involves dissociation of NEDD8 mediated by the COP9 signalosome and displacement of KBTBD2 by the inhibitor CAND1. The hereby identified structural basis of p85 alpha regulation opens the way to better understanding disturbances of glucose regulation, growth and cancer.
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Dynamic shape-shifting of the single-celled eukaryotic predator Lacrymaria via unconventional cytoskeletal components
Current biology : CB2024. Qin, Weiwei et al. Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, Hubei, China
ABSTRACT:Eukaryotic cells depend on dynamic changes in shape to fulfill a wide range of cellular functions, maintain essential biological processes, and regulate cellular behavior. The single-celled, predatory ciliate Lacrymaria exhibits extraordinary dynamic shape-shifting using a flexible "neck" that can stretch 7-8 times the length of its body to capture prey. The molecular mechanism behind this morphological change remains a mystery. We have observed that when in an active state, Lacrymaria repeatedly extends and contracts its neck to enable 360-degree space search and prey capture. This remarkable morphological change involves a unique actin-myosin system rather than the Ca2+-dependent system found in other contractile ciliates. Two cytoskeletons are identified in the cortex of the Lacrymaria cell, namely the myoneme cytoskeleton and the microtubule cytoskeleton. The myoneme cytoskeleton is composed of centrin-myosin proteins, exhibiting distinct patterns between the neck and body, with their boundary seemingly associated with the position of the macronucleus. A novel giant protein forming a ladder-like structure was discovered as a component of the microtubule cytoskeleton. Thick centrin-myosin fibers are situated very close to the right side of the ladders in the neck but are far away from such structures in the body. This arrangement enables the decoupling of the neck and body. Plasmodium-like unconventional actin has been discovered in Lacrymaria, and this may form highly dynamic short filaments that could attach to the giant protein and myosin, facilitating coordination between the two cytoskeletons in the neck. In summary, this fascinating organism employs unconventional cytoskeletal components to accomplish its extraordinary dynamic shape-shifting.
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Ribosome External Electric Field Regulates Metabolic Enzyme Activity: The RAMBO Effect
JOURNAL OF PHYSICAL CHEMISTRY B2024. Yu, Jianchao et al. Department of Chemistry, University at Albany, State University of New York, Albany, New York 12222, United States
ABSTRACT:Ribosomes bind to many metabolic enzymes and change their activity. A general mechanism for ribosome-mediated amplification of metabolic enzyme activity, RAMBO, was formulated and elucidated for the glycolytic enzyme triosephosphate isomerase, TPI. The RAMBO effect results from a ribosome-dependent electric field-substrate dipole interaction energy that can increase or decrease the ground state of the reactant and product to regulate catalytic rates. NMR spectroscopy was used to determine the interaction surface of TPI binding to ribosomes and to measure the corresponding kinetic rates in the absence and presence of intact ribosome particles. Chemical cross-linking and mass spectrometry revealed potential ribosomal protein binding partners of TPI. Structural results and related changes in TPI energetics and activity show that the interaction between TPI and ribosomal protein L11 mediate the RAMBO effect.
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Redox-modulated SNX25 as a novel regulator of GPCR-G protein signaling from endosomes
Redox Biology2024. Zhang, Yulong et al. State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
ABSTRACT:
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