Protein environment affects the water–tryptophan binding mode. MD, QM/MM, and NMR studies of engrailed homeodomain mutants

2018 ◽  
Vol 20 (18) ◽  
pp. 12664-12677 ◽  
Author(s):  
Nad'a Špačková ◽  
Zuzana Trošanová ◽  
Filip Šebesta ◽  
Séverine Jansen ◽  
Jaroslav V. Burda ◽  
...  

Water molecules can interact with the π-face of tryptophan either forming an O–H⋯π hydrogen bond or by a lone-pair⋯π interaction. Surrounding amino acids can favor the one or the other interaction type.

1948 ◽  
Vol 21 (4) ◽  
pp. 853-859
Author(s):  
R. F. A. Altman

Abstract As numerous investigators have shown, some of the nonrubber components of Hevea latex have a decided accelerating action on the process of vulcanization. A survey of the literature on this subject points to the validity of certain general facts. 1. Among the nonrubber components of latex which have been investigated, certain nitrogenous bases appear to be most important for accelerating the rate of vulcanization. 2. These nitrogen bases apparently occur partly naturally in fresh latex, and partly as the result of putrefaction, heating, and other decomposition processes. 3. The nitrogen bases naturally present in fresh latex at later stages have been identified by Altman to be trigonelline, stachhydrine, betonicine, choline, methylamine, trimethylamine, and ammonia. These bases are markedly active in vulcanization, as will be seen in the section on experimental results. 4. The nitrogenous substances formed by the decomposition processes have only partly been identified, on the one hand as tetra- and pentamethylene diamine and some amino acids, on the other hand as alkaloids, proline, diamino acids, etc. 5. It has been generally accepted that these nitrogenous substances are derived from the proteins of the latex. 6. Decomposition appears to be connected with the formation of a considerable amount of acids. 7. The production of volatile nitrogen bases as a rule accompanies the decomposition processes. These volatile products have not been identified. 8. The active nitrogen bases, either already formed or derived from complex nitrogenous substances, seem to be soluble in water but only slightly soluble in acetone.


2021 ◽  
Vol 8 ◽  
Author(s):  
Yutao Huang ◽  
Zijian Jiang ◽  
Xiangyu Gao ◽  
Peng Luo ◽  
Xiaofan Jiang

Armadillo repeat-containing proteins (ARMCs) are widely distributed in eukaryotes and have important influences on cell adhesion, signal transduction, mitochondrial function regulation, tumorigenesis, and other processes. These proteins share a similar domain consisting of tandem repeats approximately 42 amino acids in length, and this domain constitutes a substantial platform for the binding between ARMCs and other proteins. An ARMC subfamily, including ARMC1∼10, ARMC12, and ARMCX1∼6, has received increasing attention. These proteins may have many terminal regions and play a critical role in various diseases. On the one hand, based on their similar central domain of tandem repeats, this ARMC subfamily may function similarly to other ARMCs. On the other hand, the unique domains on their terminals may cause these proteins to have different functions. Here, we focus on the ARMC subfamily (ARMC1∼10, ARMC12, and ARMCX1∼6), which is relatively conserved in vertebrates and highly conserved in mammals, particularly primates. We review the structures, biological functions, evolutions, interactions, and related diseases of the ARMC subfamily, which involve more than 30 diseases and 40 bypasses, including interactions and relationships between more than 100 proteins and signaling molecules. We look forward to obtaining a clearer understanding of the ARMC subfamily to facilitate further in-depth research and treatment of related diseases.


Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 4008 ◽  
Author(s):  
Alexander Veljko Fejzagić ◽  
Jan Gebauer ◽  
Nikolai Huwa ◽  
Thomas Classen

Halogens can be very important for active agents as vital parts of their binding mode, on the one hand, but are on the other hand instrumental in the synthesis of most active agents. However, the primary halogenating compound is molecular chlorine which has two major drawbacks, high energy consumption and hazardous handling. Nature bypassed molecular halogens and evolved at least six halogenating enzymes: Three kind of haloperoxidases, flavin-dependent halogenases as well as α-ketoglutarate and S-adenosylmethionine (SAM)-dependent halogenases. This review shows what is known today on these enzymes in terms of biocatalytic usage. The reader may understand this review as a plea for the usage of halogenating enzymes for fine chemical syntheses, but there are many steps to take until halogenating enzymes are reliable, flexible, and sustainable catalysts for halogenation.


1999 ◽  
Vol 55 (4) ◽  
pp. 573-590 ◽  
Author(s):  
George Ferguson ◽  
Christopher Glidewell ◽  
Richard M. Gregson ◽  
Emma S. Lavender

The structures of six hydrogen-bonded adducts of 4,4′-sulfonyldiphenol with heteroaromatic amines have been determined. In 4,4′-sulfonyldiphenol–pyrazine (2/1) the pyrazine molecules lie across centres of inversion. The bisphenol molecules are linked into C(8) chains parallel to [100] by means of O—H...O=S hydrogen bonds, and antiparallel pairs of these chains are cross-linked by the pyrazine molecules, via O—H...N hydrogen bonds, to form molecular ladders containing R_6^6(50) rings between the rungs of the ladders. Each ladder is interwoven with two neighbouring ladders, thus producing a continuous two-dimensional sheet. The structure of 4,4′-sulfonyldiphenol–4,4′-bipyridyl (1/1) consists of spiral C_2^2(21) chains parallel to [010] containing alternating bisphenol and bipyridyl molecules linked by O—H...N hydrogen bonds: these chains are linked by two types of C—H...O hydrogen bonds which form C(5) chains along [001] and C_2^2(10) chains along [101], thus generating two interconnected nets characterized in the one case by a chequerboard pattern of R_6^6(44) and R_6^6(52) rings, and in the other by a single type of R_6^6(46) ring. 4,4′-Sulfonyldiphenol–trans-1,2-bis(4-pyridyl)ethene (1/1) [systematic name: 4,4′-sulfonyldiphenol–trans-4,4′-vinylenedipyridine (1/1)] and 4,4′-sulfonyldiphenol–1,2-bis(4-pyridyl)ethane (1/1) [systematic name: 4,4′-sulfonyldiphenol–trans-4,4′-ethylenedipyridine (1/1)] are isomorphous: the 1,2-bis(4-pyridyl)ethene component exhibits orientational disorder, corresponding approximately to a 180° rotation of ca 23% of the molecules about the N...N vector; in each compound the structure is built from C_2^2(23) chains of alternating bisphenol and bis(pyridyl) molecules connected by O—H...N hydrogen bonds, running parallel to [112] and generated by translation. The [112] chains are linked by C—H...O hydrogen bonds which generate C_2^2(12) chains parallel to [101], so forming a two-dimensional net built from R_6^6(50) rings. The structure of 4,4′-sulfonyldiphenol–4,4′-trimethylenedipyridine (1/1) consists of C_2^2(24) chains parallel to [100] generated by translation and consisting of alternating bisphenol and bis(pyridyl) molecules linked by O—H...N hydrogen bonds. Pairs of such chains are coiled together to form double helices, and pairs of such double helices, of opposite hand, are linked together by paired C—H...O hydrogen bonds in R_2^2(10) rings to form pairs of interwoven ladders in which the C_2^2(24) chains form the uprights and the R_2^2(10) rings form the rungs, between which are R_6^6(50) rings: an R_2^2(10) ring belonging to one ladder lies at the centre of an R_6^6(50) ring belonging to the other. 4,4′-Sulfonyldiphenol–4,4′-trimethylenedipiperidine–water (2/2/1) is a salt, 2C13H27N_2^+·2C12H9O4S−·H2O, containing two independent singly protonated diamine cations, two independent bisphenolate anions, and neutral water molecules. The two independent diamine cations are linked by N—H...N hydrogen bonds into C_2^2(24) chains running parallel to [001] and generated by translation, and each type of bisphenolate anion forms an independent spiral C(12) chain, also parallel to [001]. The three types of chain are linked by the water molecules: the two types of bisphenolate chain are linked by water molecules acting as double donors in O—H...O− hydrogen bonds in a C_6^4(32) chain parallel to [100], thus generating a two-dimensional net built from R_8^6(56) rings; the diamine chains are linked to these nets by means of N—H...O hydrogen bonds in which the water molecules act as acceptors and further hydrogen bonds, of N—H...O− and N—H...O=S types, link these two-dimensional nets into a continuous three-dimensional framework.


1970 ◽  
Vol 117 (539) ◽  
pp. 421-430 ◽  
Author(s):  
Hiroshi Tanimukai ◽  
Rowena Ginther ◽  
Joanne Spaide ◽  
Joao R. Bueno ◽  
Harold E. Himwich

Pollin, Cardon and Kety (18) investigated the effects of large doses of various amino acids in combination with a monoamine oxidase (MAO) inhibitor on the behaviour of schizophrenics. They found that methionine in the presence of such an inhibitor was capable of producing behavioural changes which may ‘represent a biochemically induced acute flare-up of a chronic schizophrenic process on the one hand, or a toxic delirium superimposed upon chronic schizophrenia on the other’. Brune and Himwich (8) confirmed the clinical results of Pollin et al. On the basis of their previous work indicating that tryptamine appeared in increased concentrations in the urine before and during the activation of psychotic symptoms, they suggested that under loading conditions the formation of various N,N-dimethylated indoleamines might be facilitated in the body. The tertiary indoleamines so formed might mediate the psychotic effect of methionine with a MAO inhibitor on schizophrenic patients.


1986 ◽  
Vol 66 (2) ◽  
pp. 515-521
Author(s):  
A. G. ROBERGE ◽  
R. J. BELZILE

During postweaning growth and furring, 42 male Pastel kits were distributed into four groups. One group received a conventional diet made up of raw meat and commercial cereal mix; the other groups were fed diets containing, on a wet-matter basis, 10% soybean meal, 10% soybean meal prehydrolyzed with pepsin or 10% soybean meal prehydrolyzed with papain. Dry matter, protein and energy contents were approximately the same in all diets. Weight gain over 20 wk was significantly lower in soybean meal-fed groups compared with the one fed the conventional diet. Serum amino acids and brain biogenic amines were measured. When mink were fed pepsin-treated soybean meal, there was a significant increase in serum methionine, taurine, glycine and arginine contents compared with the groups fed the conventional or soybean diets. In the pepsin-treated group, the serum urea level was significantly lower than in the groups fed untreated or papain-treated soybean meal, suggesting that pepsin treatment decreases protein catabolism. In the papain-treated group, there was more tryptophan in the serum, suggesting a greater availability for the brain and for serotonin synthesis. In this respect, comparing papain and pepsin treatments, the serotonin content was significantly higher (P < 0.01) for the papain than for the pepsin group but in the same order of magnitude as the conventional or soybean-meal groups. A greater utilization of serotonin in the pepsin group and a greater mobilization of serotonin in the papain groups seemed to dissociate these two treatments on the basis of neurotransmitter synthesis as well as of the availability of amino acids. On the other hand, whole-brain noradrenaline content was significantly decreased (P < 0.01) with both pepsin and papain treatments compared with the conventional and untreated soybean-meal groups, suggesting greater noradrenaline utilization. Key words: Mink, neurotransmitter, amino acids, soybean meal


An investigation of the infra-red absorption spectra of five amino compounds (glycine, diketopiperazine, tetramethyl-diketopiperazine, glycylglycine and urea) has been made in the region 2-8-3-6 μ . The substances were used in the form of thin crystalline layers deposited on quartz windows. The spectra are discussed with regard to the molecular structure of the compounds under consideration. The number and position of the N—H frequencies in glycine and glycyl-glycine are in agreement with the assumption that these two molecules are in the zwitterion form in the crystal. The close similarity between the spectra of diketopiperazine and tetramethyldiketopiperazine on the one hand, and the amino acids and urea on the other, proves that no lactam-lactim interchange occurs in diketopiperazine and its derivative. Both compounds are shown to possess a centre of symmetry. It follows from the experimental evidence that in all the substances investigated resonance between the C—N and 0 = 0 bonds takes place.


1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.


Author(s):  
Stefan Krause ◽  
Markus Appel

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.


2005 ◽  
Vol 44 (03) ◽  
pp. 107-117
Author(s):  
R. G. Meyer ◽  
W. Herr ◽  
A. Helisch ◽  
P. Bartenstein ◽  
I. Buchmann

SummaryThe prognosis of patients with acute myeloid leukaemia (AML) has improved considerably by introduction of aggressive consolidation chemotherapy and haematopoietic stem cell transplantation (SCT). Nevertheless, only 20-30% of patients with AML achieve long-term diseasefree survival after SCT. The most common cause of treatment failure is relapse. Additionally, mortality rates are significantly increased by therapy-related causes such as toxicity of chemotherapy and complications of SCT. Including radioimmunotherapies in the treatment of AML and myelodyplastic syndrome (MDS) allows for the achievement of a pronounced antileukaemic effect for the reduction of relapse rates on the one hand. On the other hand, no increase of acute toxicity and later complications should be induced. These effects are important for the primary reduction of tumour cells as well as for the myeloablative conditioning before SCT.This paper provides a systematic and critical review of the currently used radionuclides and immunoconjugates for the treatment of AML and MDS and summarizes the literature on primary tumour cell reductive radioimmunotherapies on the one hand and conditioning radioimmunotherapies before SCT on the other hand.


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