Structure of the {gamma}-{varepsilon} complex of cyanobacterial F1-ATPase reveals a suppression mechanism of the {gamma} subunit on ATP hydrolysis in phototrophs
F1-ATPase forms the membrane-associated segment of F0F1-ATP synthase — the fundamental enzyme complex in cellular bioenergetics for ATP hydrolysis and synthesis. Here, we report a crystal structure of the central F1 subcomplex, consisting of the rotary shaft subunit and the inhibitory subunit, from the photosynthetic cyanobacterium Thermosynechococcus elongatus BP-1, at 1.98 Å resolution. In contrast with their homologous bacterial and mitochondrial counterparts, the subunits of photosynthetic organisms harbour a unique insertion of 35–40 amino acids. Our structural data reveal that this region forms...
Source: Biochemical Journal - September 18, 2018 Category: Biochemistry Authors: Murakami, S., Kondo, K., Katayama, S., Hara, S., Sunamura, E.-i., Yamashita, E., Groth, G., Hisabori, T. Tags: Research Articles Source Type: research
Isoproterenol-induced beta-2 adrenergic receptor activation negatively regulates interleukin-2 signaling
Regulation of intracellular signaling pathways in lymphocytes is critical for cell homeostasis and immune response. Interleukin-2 (IL-2), a key regulator of lymphocytes, signals following receptor-ligand engagement and subsequent recruitment and activation of effector proteins including JAKs and STATs. Lymphocytes can also be regulated by the central nervous system through the β2 adrenergic receptor (β2AR) pathway which can affect cell trafficking, proliferation, differentiation, and cytokine production. The cross-talk between these two signaling pathways represents an important mechanism that has yet to be fully...
Source: Biochemical Journal - September 18, 2018 Category: Biochemistry Authors: Ruiz-Medina, B. E., Cadena-Medina, D. A., Esparza, E., Arrieta, A. J., Kirken, R. A. Tags: Research Articles Source Type: research
Gibberellin application ameliorates the adverse impact of short-term flooding on Glycine max L.
Flooding is an abiotic stress that creates hypoxic conditions triggered by redox potential leading to restricted growth and grain yield in plants. In the current study, we have investigated the effect of exogenous gibberellins (GA4+7) on soybean under flooding stress. A regulatory role of GAs on biochemical changes in soybean plants [including chlorophyll contents, endogenous bioactive GA1 and GA4, endogenous jasmonic acid (JA) and abscisic acid (ABA)] has been elucidated after 3 and 6 h of flooding stress. The modulation of stress-related bio-chemicals and their genetic determinants [for instance, ABA (Timing of CAB ...
Source: Biochemical Journal - September 18, 2018 Category: Biochemistry Authors: Khan, M. A., Hamayun, M., Iqbal, A., Khan, S. A., Hussain, A., Asaf, S., Khan, A. L., Yun, B.-W., Lee, I.-J. Tags: Research Articles Source Type: research
Biochemical characterization of Plasmodium complement factors binding protein for its role in immune modulation
Complement system is the first line of human defence against intruding pathogens and is recognized as a potentially useful therapeutic target. Human malaria parasite Plasmodium employs a series of intricate mechanisms that enables it to evade different arms of immune system, including the complement system. Here, we show the expression of a multi-domain Plasmodium Complement Control Protein 1, PfCCp1 at asexual blood stages and its binding affinity with C3b as well as C4b proteins of human complement cascade. Using a biochemical assay, we demonstrate that PfCCp1 binds with complement factors and inhibits complement activat...
Source: Biochemical Journal - September 14, 2018 Category: Biochemistry Authors: Sharma, S., Kumar, G., Vashishta, M., Pandey, R., Rathore, S., Chourasia, B. K., Singhal, J., Deshmukh, A., Kalamuddin, M., Paul, G., Panda, A., Tatiya, S., Rawat, K., Gupta, D., Mohmmed, A., Natarajan, K., Malhotra, P. Tags: Research Articles Source Type: research
Thermodynamic and functional characterization of the periplasmic triheme cytochrome PpcA from Geobacter metallireducens
The Geobacter metallireducens bacterium can couple the oxidation of a wide range of compounds to the reduction of several extracellular electron acceptors, including pollutants or electrode surfaces for current production in microbial fuel cells. For these reasons, G. metallireducens are of interest for practical biotechnological applications. The use of such electron acceptors relies on a mechanism that permits electrons to be transferred to the cell exterior. The cytochrome PpcA from G. metallireducens is a member of a family composed of five periplasmic triheme cytochromes, which are important to bridge the electron tra...
Source: Biochemical Journal - September 14, 2018 Category: Biochemistry Authors: Fernandes, T. M., Morgado, L., Salgueiro, C. A. Tags: Research Articles Source Type: research
Structure of ScpC, a virulence protease from Streptococcus pyogenes, reveals the functional domains and maturation mechanism
Group A Streptococcus (GAS; Streptococcus pyogenes) causes a wide range of infections, including pharyngitis, impetigo, and necrotizing fasciitis, and results in over half a million deaths annually. GAS ScpC (SpyCEP), a 180-kDa surface-exposed, subtilisin-like serine protease, acts as an essential virulence factor that helps S. pyogenes evade the innate immune response by cleaving and inactivating C-X-C chemokines. ScpC is thus a key candidate for the development of a vaccine against GAS and other pathogenic streptococcal species. Here, we report the crystal structures of full-length ScpC wild-type, the inactive mutant, an...
Source: Biochemical Journal - September 11, 2018 Category: Biochemistry Authors: Jobichen, C., Tan, Y. C., Prabhakar, M. T., Nayak, D., Biswas, D., Pannu, N. S., Hanski, E., Sivaraman, J. Tags: Research Articles Source Type: research
A copper transcription factor, AfMac1, regulates both iron and copper homeostasis in the opportunistic fungal pathogen Aspergillus fumigatus
Although iron and copper are co-ordinately regulated in living cells, the homeostatic effects of each of these metals on the other remain unknown. Here, we show the function of AfMac1, a transcriptional activator of the copper and iron regulons of Aspergillus fumigatus, on the interaction between iron and copper. In addition to the copper-specific AfMac1-binding motif 5'-TGTGCTCA-3' found in the promoter region of ctrC, the iron-specific AfMac1-binding motif 5'-AT(C/G)NN(A/T)T(A/C)-3' was identified in the iron regulon but not in the copper regulon by ChIP sequence analysis. Furthermore, mutation of the AfMac1-binding moti...
Source: Biochemical Journal - September 11, 2018 Category: Biochemistry Authors: Park, Y.-S., Kang, S., Seo, H., Yun, C.-W. Tags: Research Articles Source Type: research
The D' domain of von Willebrand factor requires the presence of the D3 domain for optimal factor VIII binding
The D'–D3 fragment of von Willebrand factor (VWF) can be divided into TIL'-E'-VWD3-C8_3-TIL3-E3 subdomains of which TIL'-E'-VWD3 comprises the main factor VIII (FVIII)-binding region. Yet, von Willebrand disease (VWD) Type 2 Normandy (2N) mutations, associated with impaired FVIII interaction, have been identified in C8_3-TIL3-E3. We now assessed the role of the VWF (sub)domains for FVIII binding using isolated D', D3 and monomeric C-terminal subdomain truncation variants of D'–D3. Competitive binding assays and surface plasmon resonance analysis revealed that D' requires the presence of D3 for effective interac...
Source: Biochemical Journal - September 11, 2018 Category: Biochemistry Authors: Przeradzka, M. A., Meems, H., van der Zwaan, C., Ebberink, E. H. T. M., van den Biggelaar, M., Mertens, K., Meijer, A. B. Tags: Research Articles Source Type: research
Structural insights into oxidation of medium-chain fatty acids and flavanone by myxobacterial cytochrome P450 CYP267B1
Oxidative biocatalytic reactions performed by cytochrome P450 enzymes (P450s) are of high interest for the chemical and pharmaceutical industries. CYP267B1 is a P450 enzyme from myxobacterium Sorangium cellulosum So ce56 displaying a broad substrate scope. In this work, a search for new substrates was performed, combined with product characterization and a structural analysis of substrate-bound complexes using X-ray crystallography and computational docking. The results demonstrate the ability of CYP267B1 to perform in-chain hydroxylations of medium-chain saturated fatty acids (decanoic acid, dodecanoic acid and tetradecan...
Source: Biochemical Journal - September 11, 2018 Category: Biochemistry Authors: Jozwik, I. K., Litzenburger, M., Khatri, Y., Schifrin, A., Girhard, M., Urlacher, V., Thunnissen, A.-M. W. H., Bernhardt, R. Tags: Research Articles Source Type: research
A frog cathelicidin peptide effectively promotes cutaneous wound healing in mice
Although cathelicidins in mammals have been well characterized, little is known about the function of cathelicidin in amphibians. In the present study, a novel 24-residue peptide (cathelicidin-NV, ARGKKECKDDRCRLLMKRGSFSYV) belonging to the cathelicidin family was identified from the skin of the plateau frog Nanorana ventripunctata. Cathelicidin-NV showed strong wound healing-promoting activity in a murine model with a full-thickness dermal wound. It directly enhanced the proliferation of keratinocyte cells, resulting in accelerated re-epithelialization of the wound site. Cathelicidin-NV also promoted the proliferation of f...
Source: Biochemical Journal - September 11, 2018 Category: Biochemistry Authors: Wu, J., Yang, J., Wang, X., Wei, L., Mi, K., Shen, Y., Liu, T., Yang, H., Mu, L. Tags: Research Articles Source Type: research
Y-box proteins combine versatile cold shock domains and arginine-rich motifs (ARMs) for pleiotropic functions in RNA biology
Y-box proteins are single-strand DNA- and RNA-binding proteins distinguished by a conserved cold shock domain (CSD) and a variable C-terminal domain organized into alternating short modules rich in basic or acidic amino acids. A huge literature depicts Y-box proteins as highly abundant, staggeringly versatile proteins that interact with all mRNAs and function in most forms of mRNA-specific regulation. The mechanisms by which Y-box proteins recognize mRNAs are unclear, because their CSDs bind a jumble of diverse elements, and the basic modules in the C-terminal domain are considered to bind nonspecifically to phosphates in ...
Source: Biochemical Journal - September 11, 2018 Category: Biochemistry Authors: Kleene, K. C. Tags: Review Articles Source Type: research
Characterizing the interaction between insulin-like growth factor 2 mRNA-binding protein 1 (IMP1) and KRAS expression
Insulin-like growth factor 2 mRNA-binding protein-1 (IMP1) has high affinity for KRAS mRNA, and it can regulate KRAS expression in cells. We first characterized the molecular interaction between IMP1 and KRAS mRNA. Using IMP1 variants with a point mutation in the GXXG motif at each KH domain, we showed that all KH domains play a critical role in the binding of KRAS RNA. We mapped the IMP1-binding sites on KRAS mRNA and show that IMP1 has the highest affinity for nts 1–185. Although it has lower affinity, IMP1 does bind to other coding regions and the 3'-UTR of KRAS mRNA. Eight antisense oligonucleotides (AONs) were d...
Source: Biochemical Journal - September 5, 2018 Category: Biochemistry Authors: Mackedenski, S., Wang, C., Li, W.-M., Lee, C. H. Tags: Research Articles Source Type: research
Prediction of secondary and tertiary structures of human BC200 RNA (BCYRN1) based on experimental and bioinformatic cross-validation
Based on experimental and bioinformatic approaches, we present the first empirically established complete secondary structure of human BC200 RNA. BC200 RNA is a brain-specific non-messenger RNA with a confirmed regulatory role in dendritic translation in neurons. Although the involvement of human BC200 RNA in various types of tumour and Alzheimer's disease has been repeatedly confirmed, the exact secondary structure remains not fully elucidated. To determine the secondary structure of BC200 RNA in vitro, we performed partial hydrolysis with sequence-specific nucleases and lead-induced cleavage. We also examined the availab...
Source: Biochemical Journal - September 5, 2018 Category: Biochemistry Authors: Sosinska-Zawierucha, P., Zawierucha, P., Breborowicz, A., Barciszewski, J. Tags: Research Articles Source Type: research
Eudesmane-type sesquiterpene diols directly synthesized by a sesquiterpene cyclase in Tripterygium wilfordii
Cryptomeridiol, a typical eudesmane diol, is the active principle component of the antispasmodic Proximol. Although it has been used for many years, the biosynthesis pathway of cryptomeridiol has remained blur. Among terpenoid natural products, terpenoid cyclases are responsible for cyclization and generation of hydrocarbon backbones. The cyclization is mediated by carbocationic cascades and ultimately terminated via deprotonation or nucleophilic capture. Isoprene precursors are, respectively, converted into hydrocarbons or hydroxylated backbones. A sesquiterpene cyclase in Tripterygium wilfordii (TwCS) was determined to d...
Source: Biochemical Journal - September 5, 2018 Category: Biochemistry Authors: Tong, Y.-r., Su, P., Guan, H.-y., Hu, T.-y., Chen, J.-l., Zhang, Y.-f., Zhao, Y.-j., Gao, L.-h., Zhang, X.-n., Huang, L.-q., Gao, W. Tags: Research Articles Source Type: research
PKA-site phosphorylation of importin13 regulates its subcellular localization and nuclear transport function
Importin 13 (IPO13) is a key member of the importin β superfamily, which can transport cargoes both into and out of the nucleus to contribute to a variety of important cellular processes. IPO13 is known to undergo phosphorylation, but the impact of this on function has not been investigated. Here, we show for the first time that IPO13 is phosphorylated by cAMP-dependent protein kinase A specifically at serine 193. Results from fluorescence recovery after photobleaching and fluorescence loss in photobleaching approaches establish that negative charge at serine 193 through phosphorylation or point mutation both reduces ...
Source: Biochemical Journal - August 31, 2018 Category: Biochemistry Authors: Liu, X., Lin, W., Shi, X., Davies, R. G., Wagstaff, K. M., Tao, T., Jans, D. A. Tags: Research Articles Source Type: research
