Engineering Nucleotide Specificity of Succinyl-CoA Synthetase in Blastocystis: The Emerging Role of Gatekeeper Residues.

PublishedJournal ArticleThis is the final version of the article. Available from American Chemical Society via the DOI in this record.Charged, solvent-exposed residues at the entrance to the substrate binding site (gatekeeper residues) produce electrostatic dipole interactions with approaching substrates, and control their access by a novel mechanism called "electrostatic gatekeeper effect". This proof-of-concept study demonstrates that the nucleotide specificity can be engineered by altering the electrostatic properties of the gatekeeper residues outside the binding site. Using Blastocystis succinyl-CoA synthetase (SCS, EC 6.2.1.5), we demonstrated that the gatekeeper mutant (ED) resulted in ATP-specific SCS to show high GTP specificity. Moreover, nucleotide binding site mutant (LF) had no effect on GTP specificity and remained ATP-specific. However, via combination of the gatekeeper mutant with the nucleotide binding site mutant (ED+LF), a complete reversal of nucleotide specificity was obtained with GTP, but no detectable activity was obtained with ATP. This striking result of the combined mutant (ED+LF) was due to two changes; negatively charged gatekeeper residues (ED) favored GTP access, and nucleotide binding site residues (LF) altered ATP binding, which was consistent with the hypothesis of the "electrostatic gatekeeper effect". These results were further supported by molecular modeling and simulation studies. Hence, it is imperative to extend the strategy of the gatekeeper effect in a different range of crucial enzymes (synthetases, kinases, and transferases) to engineer substrate specificity for various industrial applications and substrate-based drug design.Work is supported by the National Institute of Malaria Research, Indian Council of Medical Research, New Delhi and Dept. of Biotechnology, New Delhi. K.C.P. is a recipient of the Prof. Ramalingaswami Fellowship (Department of Biotechnology, Government of India (BT/HRD/35/02/2006), K.V. is a recipient of UGC Senior Research Fellowship, M.v.d.G. is grateful for support from the University of Exeter and the Wellcome Trust (078566/A/05/Z)

Flow through Multiple Well Points System

Under natural geographical settings, there are regions all over the world where the native groundwater quality is brackish. However, recharging from the surface water bodies (i.e., rivers and canals) establishes freshwater lenses in the upper portions of these brackish aquifers. Skimming of these freshwater lenses is a viable technique for sustaining livelihood and agricultural practices in these regions. In the present chapter, various skimming methods have been discussed. In addition, one another type of problem has also been developed in certain pockets of these regions. The non-withdrawal of groundwater and the excess use of easily available surface water resources (i.e., canal water) have created severe water logging conditions. Subsequently, it leads to the creation of salt‐affected soils. One of such areas located in the southwestern Punjab (India) was taken under study. Keeping the region\u27s problems in mind and considering the merits and demerits of all the skimming methods, a much efficient and affordable technique named multiple well points system (MWPS) has been proposed. The continuous use of MWPS not only reclaimed the area but also improved the groundwater quality. The system was field tested and modified before recommending to the farmers. Later on, the MWPS\u27s feasibility as a groundwater recharging system was also demonstrated in the field and the results have shown that it is a viable technique for reviving freshwater lenses in the region

Primary sclerosing cholangitis in India

Six patients with PSC have been diagnosed and followed up at a centre in Northern India for periods upto 4 years. They all presented with cholestatic jaundice and cholangitis, but one of them subsequently presented with variceal haemorrhage. Cholangiographic features were the most characteristic and included irregular narrowing and segmental dilatation of the biliary radicles giving them a beaded appearance. Treating them was most frustrating. Two of them died of hepatic encephalopathy, others have also continued to be sick during the follow-up

Sums of matrix-valued wave packet frames in (L^2(ℝ^d,ℂ^{stimes r}))

The purpose of this paper is to first show relations between wave packet frame bounds and the scalars associated with finite sum of matrix-valued wave packet frames for the matrix-valued function space (L^2(ℝ^d, ℂ^{stimes r}). A sufficient condition with explicit wave packet frame bounds for finite sum of matrix-valued wave packet frames in terms of scalars and frame bounds associated with the finite sum of frames is given. An optimal estimate of wave packet frame bounds for the finite sum of matrix-valued wave packet frames is presented. In the second part, we show that the rate of convergence of the frame algorithm can be increased by using frame bounds and scalars associated with the finite sum of frames. Finally, a necessary and sufficient condition for finite sum of matrix-valued wave packet frames in terms of series associated with wave packet vectors is given

Gag Deadens but doesn't Mute the Crime: a Case Series of Homicidal Gagging

Background: Asphyxia is the commonest mode of death in various violent homicidal deaths and in majority of such cases, there may not be any evidence of external injury except the general features of asphyxia being the only proof to rely upon. Under such circumstances, even an experienced medicolegal expert may not go further than to declare the death to be due to asphyxia; the exact mode adopted being left unexplained.Case Report: We present here a case report of three family members who were killed by means of gagging with the motive of taking over the property.Conclusion: Deaths due to gagging is rare but most of the times homicidal. This case was peculiar as there were multiple individuals who were gagged simultaneously and their bodies were stuffed into trunk

Estimating Tourist Growth at Destination Sites: A Mathematical Equation and a Connectivity Model Through Mobile Application

لقد سعى باحثو العلوم الاجتماعية إلى عرض الأدبيات المختلفة لأنظمة التوصية المتنقلة الفردية لمساعدة أصحاب المصلحة في قطاع السياحة. إن التحدي المتمثل في صياغة معادلة رياضية للتنبؤ بالنمو السياحي في مواقع محددة ينشأ بسبب الظروف البيئية المتنوعة الفريدة لكل وجهة. يسعى هذا البحث إلى تطوير نموذج لتطبيقات الهاتف المحمول يعزز الاتصال بين أصحاب المصلحة الرئيسيين في مجال السياحة. داخل التطبيق، يمكن لأصحاب المصلحة استرداد المعلومات حول الآخرين بسهولة والتفاعل مباشرة مع السلطات ذات الصلة دون الخروج من التطبيق. يوفر التطبيق أيضًا إرشادات ملاحية للوجهات السياحية. وتستكشف الدراسة معدل النمو النوعي للسياح، بافتراض تضاعف أعداد السياح بعد فترة زمنية محددة. في حين أنه قد يكون هناك نمو هائل مبدئي في أعداد السياح في الوجهة، إلا أن العدد يستقر في النهاية. تم استخدام معادلة مونود مع المعادلة السياحية للحصول على تمثيل شامل في هذه الدراسة. بالإضافة إلى ذلك، يتعمق البحث في التحليل الرسومي لشروط الجدوى التي يقترحها نموذج الاتصال الخاص بـCasagrand i و Rinaldi. و من الضروري ملاحظة أن هذا التحليل يظل مجردًا، وأن إنشاء نموذج رياضي رياضي قابل للتطبيق عالميًا لكل وجهة يكاد يكون مستحيلًا.Social science researchers have endeavored with the literature showcasing various individual mobile recommendation systems to assist stakeholders in the tourism sector. The challenge of formulating a mathematical equation to predict tourist growth at specific sites arises due to the diverse environmental conditions unique to each destination. This research seeks to develop a mobile application model fostering connectivity among significant tourism stakeholders. Within the app, stakeholders can effortlessly retrieve information about others and directly engage with relevant authorities without exiting the application. The app also provides navigation guidance to tourist destinations. The study explores the specific growth rate of tourists, assuming a doubling of tourist numbers after a specific time interval has been illustrated. While there may be an initial exponential growth in tourist numbers at a destination, the count eventually stabilizes. The Monod equation is employed in conjunction with the tourist equation for a comprehensive representation in this study. Additionally, the research delves into the graphical analysis of the feasibility conditions proposed by Casagrandi and Rinaldi's connectivity model. It is essential to note that this analysis remains abstract, and the creation of a universally applicable mathematical tourism model for every destination proves nearly impossible

An approach for the identification of targets specific to bone metastasis using cancer genes interactome and gene ontology analysis

Metastasis is one of the most enigmatic aspects of cancer pathogenesis and is a major cause of cancer-associated mortality. Secondary bone cancer (SBC) is a complex disease caused by metastasis of tumor cells from their primary site and is characterized by intricate interplay of molecular interactions. Identification of targets for multifactorial diseases such as SBC, the most frequent complication of breast and prostate cancers, is a challenge. Towards achieving our aim of identification of targets specific to SBC, we constructed a 'Cancer Genes Network', a representative protein interactome of cancer genes. Using graph theoretical methods, we obtained a set of key genes that are relevant for generic mechanisms of cancers and have a role in biological essentiality. We also compiled a curated dataset of 391 SBC genes from published literature which serves as a basis of ontological correlates of secondary bone cancer. Building on these results, we implement a strategy based on generic cancer genes, SBC genes and gene ontology enrichment method, to obtain a set of targets that are specific to bone metastasis. Through this study, we present an approach for probing one of the major complications in cancers, namely, metastasis. The results on genes that play generic roles in cancer phenotype, obtained by network analysis of 'Cancer Genes Network', have broader implications in understanding the role of molecular regulators in mechanisms of cancers. Specifically, our study provides a set of potential targets that are of ontological and regulatory relevance to secondary bone cancer.Comment: 54 pages (19 pages main text; 11 Figures; 26 pages of supplementary information). Revised after critical reviews. Accepted for Publication in PLoS ON