Crystal structures of a series of bis(acetylacetonato)oxovanadium(IV) complexes containing N-donor pyridyl ligands

Crystal structures for a series of bis(acetylacetonato)oxovanadium(IV) complexes containing N-donor pyridyl ligands are reported, namely, bis(acetylacetonato-κ2 O,O′)oxido(pyridine-κN)vanadium(IV), [V(C5H7O2)2O(C5H5N)], 1, bis(acetylacetonato-κ2 O,O′)oxido(pyridine-4-carbonitrile-κN)vanadium(IV), [V(C5H7O2)2O(C6H4N2)], 2, and bis(acetylacetonato-κ2 O,O′)(4-methoxypyridine-κN)oxidovanadium(IV), [V(C5H7O2)2O(C6H7NO)], 3, Compounds 1–3 have the formulae VO(C5H7O2)2 L, where L = pyridine (1), 4-cyano-pyridine (2), and 4-methoxypyridine (3). Compound 1 was previously reported [Meicheng et al. (1984). Kexue Tongbao, 29, 759–764 and DaSilva, Spiazzi, Bortolotto & Burrow (2007). Acta Crystallogr., E63, m2422] and redetermined here at cryogenic temperatures. Compounds 1 and 2 as pyridine and 4-cyanopyridine adducts, respectively, crystallize as distorted octahedral structures with the oxo and pyridyl ligands trans to one another. A crystallographic twofold axis runs through the O—V—N bonds. Compound 3 containing a 4-methoxypyridine ligand crystallizes as a distorted octahedral structure with the oxo and pyridyl ligands cis to one other, removing the twofold symmetry seen in the other complexes.

Crystal structure of mechanochemically synthesized Ag2CdSnS4

Ag2CdSnS4 was synthesized by a two step mechanochemical synthesis route. From a detailed analysis of the observed reflections in the X-ray powder diffraction pattern, the crystal structure proposed in the literature (space group Cmc21 [E. Parthé, K. Yvon, R. H. Deitch, Acta Crystallogr.1969, B25, 1164–1174; O. V. Parasyuk, I. D. Olekseyuk, L. V. Piskach, S. V. Volkov, V. I. Pekhnyo, J. Alloys Compd.2005, 399, 173–177]) is questionable. Our structural investigations presented in this contribution point to the fact that Ag2CdSnS4 crystallizes in the monoclinic wurtzkesterite-type structure (space group Pn). At around T = 200°C, a phase transition to the orthorhombic wurtzstannite-type structure (space group Pmn21) is observed.

Оптимизация методики получения рекомбинантных двухдоменных лакказ

Лакказы (К.Ф. 1.10.3.2) – ферменты из семейства медьсодержащих оксидаз, активный центркоторых содержит 4 атома меди. Лакказы способны окислять широкий спектр органический и неорганических соединений. Ферменты данного класса используют в биотехнологических целях (в целлюлозно-бумажной, текстильной, пищевой промышленности). В структурном отношении лакказыподразделяют на 2 группы: двухдоменные (2д) и трёхдоменные (3д) ферменты. Характерные особенности 2д лакказ – устойчивость к специфичным ингибиторам семейства медьсодержащих оксидаз, а также высокая термостабильность. Окислительно-восстановительный потенциал 2д лакказ ниже потенциала 3д ферментов. Однако он может быть повышен благодаря использованию редоксмедиаторов. Высокая термостабильность и устойчивость к действию ингибиторов – важные критерии отбора ферментов для нужд биотехнологии. Также важным критерием для биотехнологически значимых ферментов является стоимость их производства. Если получение фермента требует значительных затрат, а выход конечного продукта низок, то производство фермента нецелесообразно.Поэтому целью данной работы является оптимизация процесса получения двухдоменных рекомбинантных лакказ, экспрессируемых гетерологично в штамме Escherichia coli, с расчетами стоимости конечного продукта (на примере ферментов SgfSL, SvSL и SaSL, полученных в нашей лаборатории). Ранее три рекомбинантные двухдоменные лакказы были клонированы и экспрессированы в штамме Escherichia coli M15 (pRep4). В данной работе мы исследовали влияние различных факторов на максимальный выход лакказ: влияние ионов меди, концентрации индуктора, условий культивирования, оптической плотности культуры, и других условий. Было показано, что оптимальная концентрация ионов меди составляет 1 мМ, а оптимальная концентрация индуктора ИПТГ составляет 0,1мМ (при этом отсутствует эффект агрегирования и наблюдается высокий выход ферментов). Мы подтвердили выводы коллег о том, что для получения лакказ, максимально насыщенных ионами меди, необходимы микроаэробные условия культивирования. Без стадии микроаэробного роста удельная активность очищенных ферментов снижается в 2 раза. Было обнаружено, что слишком высокая скорость перемешивания клеток при индукции синтеза лакказ приводит к агрегации ферментов. Скорость перемешивания, при которой лакказы не агрегируют, составляет 50-100 об/мин.Выводы: был разработан и оптимизирован процесс получения двухдоменных бактериальныхрекомбинантных лакказ. Максимальный выход ферментов составил 180 мг белка с литра среды. Фер-мент имел низкую себестоимость (16-32 евро за 1 г белка). ЛИТЕРАТУРА 1. Baldrian P. // FEMS Microbiol Lett. 2006. Vol. 30. No 2. pp. 215-242.2. Claus H. // Arch Microbiol. 2003. Vol. 179. No 3. pp. 145-150.3. Otto B., Schlosser D. // Planta. 2014. Vol. 240. No 6. pp. 1225-1236.4. Lisov A.V., Zavarzina A.G., Zavarzin A.A., Leontievsky A.A. // FEMS Microbiol Lett.2007. Vol. 275. No 1. pp. 46-52.5. Thurston C.F. // Microbiology. 1994. Vol. 140. pp. 19-26.6. Sterjiades R., Dean J.F., Eriksson K.E. // Plant Physiol. 1992. Vol. 99. No 3. pp. 1162-1168.7. Endo K., Hosono K., Beppu T., Ueda K. // Microbiology. 2002. Vol. 148. pp. 1767-1776.8. Lu L., Zeng G., Fan C., Zhang J. et al. // Appl Environ Microbiol. 2014. Vol. 80. No 11. pp. 3305-3314.9. Minussi R.C., Pastore G.M., Duran N. // Trends Food Sci Tech. 2002. Vol. 13. No 6-7. рр. 205-216.10. Dominguez A., Couto S.R., Sanroman M.A. // World J Microbiol Biotechnol. 2005. Vol. 21. No 4. pp. 405-409.11. Couto S.R., Herrera J.L.T. // Biotechnol Adv. 2006. Vol. 24. No 5. pp. 500-513.12. Trubitsina L.I., Tishchenko S.V., Gabdulkhakov A.G., Lisov A.V. et al. // Biochimie.2015. Vol. 112. pp. 151-159.13. Tishchenko S., Gabdulkhakov A., Trubitsina L., Lisov A. et al. // Acta Crystallogr F Struct Biol Commun. 2015. Vol. 71. pp. 1200-1204.14. Lisov A.V., Trubitsina L.I., Lisova Z.A., Trubitsin I.V. et al. // Process biochemistry. 2019. Vol. 76. pp. 128-135.15. Durao P., Chen Z., Fernandes A.T., Hildebrandt P. et al. // J Biol Inorg Chem. 2008. Vol. 13. No 2. pp. 183-193.16. Gunne M., Urlacher V.B. // PLoS One. 2012. Vol. 7. No 12. pp. e52360.

Высокотемпературная кубическая модификация сульфида галлия (хs = 59 мол %) и Т, х-диаграмма системы Ga – S

Уточнена фазовая диаграмма системы Ga – S в области составов от 30.0 до 60.7 mol % серы и в области температур от комнатной до 1220 °С. Выделена и структурно охарактеризована фаза s-Ga2S3, имеющая сфалеритоподобную структуру (пр. гр. , параметр решетки 5.21 Å) с дефицитом атомов в подрешетке галлия, существование которой подтверждено также термическими методами анализа. Определены температурные зависимости параметров решеток моноклинной фазы a-Ga2S3 (Cc) и гексагональной слоистой фазы b-GaS (P63/mmc), причем показано, что параметр c последней существенно зависит от температуры вследствие увеличения ван-дер-ваальсовой щели. ИСТОЧНИК ФИНАНСИРОВАНИЯ Работа выполнена при финансовой поддержке РФФИ, проект 18-33-00900-мол-а. ЛИТЕРАТУРА Kogler M., Kock E. M., Klotzer B., Penner S. Phys. Chem. – Amer. Chem. Soc., 2016, vol. 120, iss. 39, pp. 22443–22454. https://doi.org/10.1021/acs.jpcc.6b07234 Lokshin E. P., Sidneva T. A. prikl. chim. [Russian Journal of Applied Chemistry], 2006, vol. 79, iss. 8, pp. 1220–1224. https://doi.org/10.1134/s1070427206080027 Xu M., Liang T., Shi M., Chen H. Rev., 2013, vol. 113, pp. 3766–3798. https://doi.org/10.1021/cr300263a Zhang M. J., Jiang X. M., Zhou L. J., Guo G. C. Mater. Chem., vol. C1, 2013. pp. 4754–4760. https://doi.org/10.1039/c3tc30808a Parthé E. Elements of Inorganic Structural Chemistry. Wien, 1990, 144 p. Pardo M., Tomas A., Guittard M. Res. Bull., 1987, vol. 22, pp. 1677–1684. https://doi.org/10.1016/0025-5408(87)90011-0 Pardo M. P., Guittard M., Chilouet A. Pardo M. P., Guittard M., Chilouet A. Solid State Chem., 1993, vol. 102, pp. 423–433. https://doi.org/10.1006/jssc.1993.1054 Ormont B. F. Vvedenie v physicheskuyu chimiyu i cristallochimiyu poluprovodnikov [Introduction to Physical Chemistry and Crystal Chemistry of Semiconductors]. Moscow, Vysshaya shkola Publ., 1982, 528 p. (in Russ.) Berezin S. S., Zavrazhnov A. Yu., Naumov A. V. , Nekrylov I. N., Brezhnev N. Yu. Condensed Matter and Interphases, 2017, vol. 19, no. 3, pp. 321–335. URL: https://journals.vsu.ru/kcmf/article/view/208/26 (in Russ.) Zavrazhnov A., Berezin S., Kosyakov A., Naumov A., Berezina, Brezhnev N. J. Thermal Analysis and Calorimetry, 2018, vol. 134, iss. 1, pp. 483–492. https://doi.org/10.1007/s10973-018-7124-z Nolze G., Kraus W. Powder Diffraction, 1998, vol. 13, no. 4, pp. 256–259. Holland J. B., Redfern S. A. T. J. Appl. Cryst., 1997, vol. 30, p. 84. https://doi.org/10.1107/s0021889896011673 Goodyear J., Steigmann G. A. Acta Crystallogr., 1963, vol. 16, pp. 946–949. https://doi.org/10.1107/s0365110x63002565 Kuhn A., Bourdon A., Rigoult J., Rimsky A. Rev. B, 1982, v. 25, iss. 6, pp. 4081 – 4088. https://doi.org/10.1103/physrevb.25.4081 Hahn H., Klingler W. Anorg. Allgem. Chemie, 1949, vol. 259, pp. 135–142. https://doi.org/10.1002/zaac.19492590111 Webster J. Wiley Encyclopedia of Electrical and Electronics Engineering. John Wiley & Sons, 1999, pp. 147–158. https://doi.org/10.1002/047134608x Pardo M.P., Guittard M., Chilouet A. Pardo M.P., Guittard M., Chilouet A. Solid State Chem., 1993, vol. 102, pp. 423–433. https://doi.org/10.1006/jssc.1993.1054 Webster J. Wiley Encyclopedia of Electrical and Electronics Engineering. John Wiley & Sons, 1999, pp. 147–158. https://doi.org/10.1002/047134608x Berezin S. S., Berezina V., Zavrazhnov A. Yu. Inorganic Materials, 2013, vol. 49, no. 6, pp. 555–563.https://doi.org/10.1134/s0020168513060010 Streetman G. Solid State Electronic Devices, Pearson, 2016, 621 p.

Structural analysis and interaction studies of acyl-carrier protein (acpP) of Staphylococcus aureus, an extraordinarily thermally stable protein

Acyl-carrier-protein (acpP) is an essential protein in fatty acid biosynthesis of Staphylococcus aureus [Cronan, J.E. and Thomas, J. (2009). Complex enzymes in microbial natural product biosynthesis, part B: polyketides, aminocoumarins and carbohydrates. Method. Enzymol. 459, 395–433; Halavaty, A.S., Kim, Y., Minasov, G., Shuvalova, L., Dubrovska, I., Winsor, J., Zhou, M., Onopriyenko, O., Skarina, T., Papazisi, L., et al. (2012). Structural characterization and comparison of three acyl-carrier-protein synthases from pathogenic bacteria. Acta Crystallogr. Sect. D Biol. Crystallogr. 68, 1359–1370]. The inactive apo-form is converted to the active holo-enzyme by acyl-carrier protein synthase (acpS) through addition of a 4′-phosphopantetheine group from coenzyme A to a conserved serine residue of acpP [Flugel, R.S., Hwangbo, Y., Lambalot, R.H., Cronan, J.E., and Walsh, C.T. (2000). Holo-(acyl-carrier protein) synthase and phosphopantetheinyl transfer in Escherichia coli. J. Biol. Chem. 275, 959–968; Lambalot, R.H. and Walsh, C.T. (1995). Cloning, overproduction, and characterization of the Escherichia coli holo-acyl-carrier protein synthase. J. Biol. Chem. 270, 24658–24661]. Once activated, acpP acts as an anchor for the growing fatty acid chain. Structural data from X-ray crystallographic analysis reveals that, despite its small size (8 kDa), acpP adopts a distinct, mostly α-helical structure when complexed with acpS [Halavaty, A.S., Kim, Y., Minasov, G., Shuvalova, L., Dubrovska, I., Winsor, J., Zhou, M., Onopriyenko, O., Skarina, T., Papazisi, L., et al. (2012). Structural characterization and comparison of three acyl-carrier-protein synthases from pathogenic bacteria. Acta Crystallogr. Sect. D Biol. Crystallogr. 68, 1359–1370; Byers, D.M. and Gong, H. (2007). Acyl carrier protein: structure–function relationships in a conserved multifunctional protein family. Biochem. Cell Biol. 85, 649–662]. We expressed and purified recombinant, active S. aureus acpP from Escherichia coli and mimicked the beginning of fatty acid biosynthesis by employing an [14C]-acp loading assay. Surprisingly, acpP remained functional even after heat treatment at 95°C for up to 10 min. NMR data from 2D-HSQC experiments as well as interaction studies with acpS confirmed that acpP is structured and active both before and after heat treatment, with no significant differences between the two. Thus, our data suggest that S. aureus acpP is a highly stable protein capable of maintaining its structure at high temperatures.

A designed repeat protein as an affinity capture reagent

Repeat proteins are an attractive target for protein engineering and design. We have focused our attention on the design and engineering of one particular class: tetratricopeptide repeat (TPR) proteins. In previous work, we have shown that the structure and stability of TPR proteins can be manipulated in a rational fashion [Cortajarena (2011) Prot. Sci. 20, 1042–1047; Main (2003) Structure 11, 497–508]. Building on those studies, we have designed and characterized a number of different peptide-binding TPR modules and we have also assembled these modules into supramolecular arrays [Cortajarena (2009) ACS Chem. Biol. 5, 545—552; Cortajarena (2008) ACS Chem. Biol. 3, 161—166; Jackrel (2009) Prot. Sci. 18, 762—774; Kajander (2007) Acta Crystallogr. D Biol. Crystallogr. 63, 800—811]. Here we focus on the development of one such TPR–peptide interaction for a practical application, affinity purification. We illustrate the general utility of our designed protein interaction. Furthermore, this example highlights how basic research on protein–peptide interactions can lead to the development of novel reagents with important practical applications.

Thallium manganese sulfate hexahydrate, a missing Tutton’s salt, and a brief review of the entire family

A new Tutton’s salt Tl2[Mn(OH2)6](SO4)2 was grown from aqueous solutions and characterized by chemical analysis and X-ray powder diffraction. It was found to be monoclinic, space group P21/a, a=0.93276(6), b=1.25735(8), c=0.62407(4) nm, and β=106.310(3)°. It is unstable in warm air and dissolves incongruently. A comparison of unit cell volumes for all 37 Tutton sulfate phases found in ICDD’s PDF-2 database (86 entries) reveals a reasonable correlation with Shannon and Prewitt’s ionic radii [Acta Crystallogr. 25, 925–926 (1969)] and several deviations, most of them seeming to be erroneous entries.

An elementary introduction to superspace crystallography

Aperiodic crystals are defined as a crystalline state of matter, that has atomic structures with long-range order but without translational symmetry. Experimentally, they are characterized by sharp Bragg reflections in the X-ray diffraction, that can be indexed by integers, if four or more reciprocal basis vectors are used. An introduction is given to the basic concepts of the superspace theory for structural analysis of incommensurately modulated crystals and incommensurate composite crystals [De Wolff, Janner and Janssen, Acta Crystallogr.

The Low-Temperature Polymorph of Tetramethyldiphosphinebis( monoborane): Insight into the Stabilization of Different Rotational Isomers in the Solid State

The low-temperature (LT) polymorph of tetramethyldiphosphine-bis(monoborane), Me2(H3B)PP( BH3)Me2, was obtained by crystallization from diethyl ether at 4 °C. It crystallizes in the monoclinic space group P21/c, a = 6.464(1), b = 7.605(1), c = 11.867(2) Å , β = 119.99(1)° (at 153 K) with 2 molecules per unit cell. This implies that the individual molecules have crystallographic inversion symmetry and a strict anti arrangement with respect to the central B-P-P-B skeleton. At 87.6 °C (DTA) the LT polymorph transforms to the high-temperature (HT) modification which contains the anti and gauche conformers in a 1:2 ratio (P21/c, Z = 6; H. L. Carrell, J. Donohue, Acta Crystallogr. B24, 699 (1968)). This strongly suggests that the gauche conformer is higher in energy and stabilized by the crystal packing of the HT modification. The P-P-B angle in the anti LT form (113.91(6)°) ascertains the value of the anti conformer in the HT form (114.4(6)°) which was found to be significantly different from the gauche conformer which centered around 110 °C.

Isolated versus Condensed Anion Structure V: X-ray Structure Analysis and 81Br NQR of t-butylammonium tribromocadmate(II)-1/2 water, i-propylammonium tribromocadmate(II), and tris-trimethylammonium heptabromodicadmate(II)

The crystal structures of the condensed bromocadmate anions with chains built of [CdBr3]∞ were de-termined by X-ray structure analysis at 300 K. In addition, the temperature dependence of the 81Br NQR frequencies was observed. [(t-C4H9NH3)CdBr3]2-H2O (1) tallizes with a double Br bridged chain (monoclinic, P2/c, Z = 4, a = 1963.4(8), b 87.7(4), c 1432.1(6) pm, and ß= 110.66(2)°). Six 81Br NQR lines are observed at temperatures between 77 and 330 K. (i-C3H7NH-3)CdBr3 (2) crystalliz-es with a triple Br bridged chain (orthrhombic, Pbca, Z= 8, a = 1975.4(6), b = 1415.8(4), c = 690.1(2) pm). (2) shows three 81Br NQR lines at temperatures between 77 and 193 K. A phase transition occurs at 224 K. The structure of [(CH3)3 NH]3Cd2Br7] (3) was redetermined. (3) consists of a triple Br bridged chain and a discrete [CdBr4] tetrahedron (hexagonal, P63mc, Z= 8, a = 1483.5(2), c = 685.7(5) pm). The structure of (3) is identical to the one reported by Daoud, Perret, and Dusausoy, Acta Crystallogr., B35, 2718 (1979). Three 81Br NQR lines are observed at temperatures between 77 and 243 K.