Innovations and Advances in Chemical Sciences, (InAdvanCS...

Innovations and Advances in Chemical Sciences, (InAdvanCS-2021)

School of Chemical Sciences Indian Association for the Cultivation of Science

Date: January 19, 2021

Programme Schedule ****************************************************************************************** Session 1

Link: https://meet.google.com/nki-vgzm-nif Time Speaker Title of the talk

10:00 AM -11.00 AM Prof. Jyotirmoyee Dash Small molecules, DNA and Self-assembly

11.00 AM -12.00 Noon Dr. Biman Jana Modeling the effect of disease related mutation and anesthetic drug molecule binding on kinesin functionality

12.00 noon – 1.00 PM Prof. Somdatta Ghosh Dey Alzheimer's Disease: Small Molecule Interactions with Heme and Copper bound Amyloid β Peptides

01.00 PM: Felicitation of Prof. Jyotirmoyee Dash by the School of Chemical Sciences followed by Lunch.

Session 2

Link: https://meet.google.com/xfq-hghq-fyd Time Speaker Title of the talk 2:00 PM - 3:00 PM Dr. Joyram Guin Asymmetric Catalysis with N-Heterocyclic Carbene

3.00 PM – 0.00 PM Dr. Amit Majumdar

Comparative Reactivity of Thiolates and Hydrosulfides with Nitric Oxide in Nonheme Diiron(II) Complexes

4.00 PM - 5:00 PM Dr. Prashant C. Singh Structure of the Hydrated Proton at the Membrane Interfaces: Vibrational Sum Frequency Generation Study

https://meet.google.com/nki-vgzm-nifhttps://meet.google.com/xfq-hghq-fyd

Abstracts

Small molecules, DNA and Self-assembly Jyotirmayee Dash

School of Chemical Sciences, Indian Association for the Cultivation of Science (IACS), Kolkata – 700032, INDIA. Email: [email protected]

This talk will highlight an outline of our activities throughout my research career. In the first half, our work on development of new methods for the synthesis of small molecule heterocycles like indoles, carbazoles and pyridoindoles will be discussed.1,2,3

Small heterocyclic compounds which bind to DNA and alter its function are considered as potential anticancer agents. Next, our efforts on developing different classes of ligands to target DNA quadruplex, a four stranded DNA secondary structure will be thrown light upon.3 DNA secondary structures play key regulatory roles in biological system. The use of DNA as a template to synthesize its own ligands by Target Directed Synthesis will also be presnted.4

Natural nucleosides present in DNA can self-assemble to mimic DNA secondary structures. The last part of my talk would focus on our work on self-assembly of nucleosides to form hydrogels and ion channels.5

N

N N

N

O

N

NN

N N

O

N

N

NN

NO

N

NN

NN

O

N

H

H

H

HHH

H

H

H

HH

H

R

R

R

R

References: 1, (a) Mandal, T.; Chakraborti, G.; Karmakar, S.; Dash, J. Org. Lett. 2018, 20, 4759. (b) Dhara, K.; Mandal. T.; Das, J.; Dash, J. Angew. Chem. Int. Edn., 2015, 54, 15831. 2. (a) Mandal, T.; Chakraborti, G.; Maiti, S.; Dash, J. Org. Let. 2019, 21, 8044. (b) Chakraborti, G.; Paladhi, S.; Mandal, T.; Dash, J. J. of Org. Chem. 2018, 83, 7347. 3. Saha, P.; Panda, D.; Dash, J. Chem. Commun. 2019, 55, 731-750. (a) Saha, P.; Panda, D.; Müller, D.; Maity, A.; Schwalbe, H.; Dash, J. Chem. Sci. 2020, 11, 2058. (b) Panda, D.; Saha, P.; Das, T.; Dash, J. Nat. Commun. 2017, 8, 16103. (5) Bhattacharyya, T.; Saha, P.; Dash, J. ACS Omega, 2018, 3, 2230.

mailto:[email protected]

Modeling the effect of disease related mutation and anesthetic drug molecule binding on kinesin functionality

Biman Jana


Inside the cell, there are spatial compartment like structures where different compartments execute dissimilar biological processes at the same time providing an immensely complex heterogeneous environment. To execute this important task of carrying out such vastly contrasting activities in different regions inside a single cell, the transport of essential cargoes connecting those compartments is required. ATP-fueled motor proteins are important for the directional transport of various proteins, organelles, and mRNAs. Kinesin-1 (Kif5) is a widely expressed, but neuron-enriched, microtubule (MT) motor that drives the outward, plus-end-directed, cytoplasmic transport of numerous vesicles and organelles and signaling complexes. Mutations in the kinesin-1 have been linked to patients identified with hereditary spastic paraplegia (HSP). HSP is a genetically and clinically heterogeneous illness that causes progressive damage of axons. In this talk, we will discuss about the effect of those mutations on the functionalities of the kinesin. Especially, the modulation of pre-organization geometry of ATP hydrolysis reaction through second sphere interactions by a disease related residues will be discussed. In the last part of the talk, we will show that a small molecule anesthetic drug (propofol) binds at two crucial binding sites on the motor domain of kinesin which disrupts the coordination required for long distance walk for kinesin.

References:

(1) Mandira Dutta, Michael R. Diehl, José N. Onuchic*, and Biman Jana* PNAS (2018), 114 E8611-E8617.

(2) Qian Wang, Michael R. Diehl, Biman Jana, Margaret S. Cheung, Anatoly B. Kolomeiskya, José N. Onuchic*, PNAS (2017), 114, E8611-E8617.

(3) Mandira Dutta, Susan P. Gilbert, José N. Onuchic*, and Biman Jana* PNAS (2021) (Accepted)

(4) Rabindranath Manna, Biman Jana* (Submitted for publication).


Alzheimer's Disease: Small Molecule Interactions with Heme and Copper bound Amyloid β Peptides

Somdatta Ghosh Dey


Alzheimer’s disease (AD) is a neurodegenerative disorder that has generally been associated with the accumulation of amyloid beta (Aβ) peptides and formation of partially reduced oxygen species (PROS) catalyzed by Cu bound Aβ active sites in the brain. Heme binding to Aβ peptides has opened up a new direction in this field. The active site environments of heme-Aβ and Cu-Aβ defined using several spectroscopic techniques and site directed mutagenesis will be discussed. These complexes react with O2 to generate reactive oxygen species. Additionally, they can act as peroxidases and degrade neurotransmitters like serotonin through highly reactive oxygen intermediates. These entities can interact with physiologically available signaling molecules like NO and exhibit interesting reactivities.

References:

1. Substrate Oxidation by Cu-A: Active oxidants involved. Nath, Arnab, K.; Ghatak, Arnab; *Dey, Abhishek;

*Dey, Somdatta Ghosh. Chemical Science, 2021 (ASAP).

2. Formation of Compound I in Heme bound Aβ-peptides relevant to Alzheimer’s Disease. Pal, Ishita; Nath,

Arnab, K.; Roy, Madhuparna; Seal, Manas; Ghosh, Chandradeep; *Dey, Somdatta Ghosh. Chemical Science, 2019, 10(36), 8405-8410.

Serotonin (5-HT)

Mononuclear copperhydroperoxo

Bis(µ-oxo)

OxidizedSerotonin


Asymmetric Catalysis with N-Heterocyclic Carbene

Joyram Guin

School of Chemical Sciences, Indian Association for the Cultivation of Science (IACS), Kolkata – 700032, INDIA. E – mail: [email protected]

In the domain of asymmetric organocatalyst, chiral N-heterocyclic carbenes (NHCs) have received significant interest. The ability of NHC to activate a diverse class of substrates via different modes of interaction is particularly intriguing.1 Accordingly, asymmetric NHC-catalysis involving covalent interaction with substrates possessing activated carbonyl functional group, Lewis acid-base interaction with silicon or boron reagents and hydrogen bonding interaction with the substrates in the presence of a proton shuttle4 have been developed. Furthermore, attempts have also been made in developing asymmetric NHC-catalysis via ion-pairing interaction with substrates utilizing the intrinsic Brønsted base characteristic of NHCs without having much success. Our group is actively working on the development of novel enantioselective organic transformations using NHC-catalysis via covalent as well as ion-pairing interaction with substrates. Some recent findings 2 of our group on asymmetric NHC-catalysis will be discussed during the lecture.

N NN

Ar

Nu

X

NN

NAr

H

NNN A

r

HO

R

NN

NAr

NN

NAr

H

chiral NHC

*

**

**

RCHO X-Nu

H-Nu H-Nu

c) H-Bonding interaction d) Ion-pairing interaction

a) Covalent interaction b) Lewis acid-base interaction

Nu

Nu

X = B

References:

1. (a) D. M. Flanigan, F. Romanov-Michailidis, N. A. White and T. Rovis, Chem. Rev., 2015, 115, 9307-9387; (b) M. N. Hopkinson, C. Richter, M. Schedler and F. Glorius, Nature, 2014, 510, 485.

2. (a) A. Porey, B. D. Mondal and J. Guin, Angew. Chem. Int. Ed., (Just accepted,

doi.org/10.1002/anie.202015004); (b) S. Santra, A. Porey, B. Jana and J. Guin, Chem. Sci., 2018, 9, 6446-6450; (c) A. Porey, S. Santra and J. Guin, J. Org. Chem., 2019, 84, 5313-5327; (d) S. Santra, U. Maji and J. Guin, Org. Lett., 2020, 22, 468-473.


Comparative Reactivity of Thiolates and Hydrosulfides with Nitric Oxide in Nonheme Diiron(II) Complexes

Amit Majumdar

School of Chemical Sciences, Indian Association for the Cultivation of Science (IACS), Kolkata-700032, India. Email: [email protected]

An extensive study has been carried out to examine the reactivity of thiolate coordinated nonheme diiron(II) complexes [1] towards NO and NO+. The products of these reactions, namely a mononitrosyl- [2] and a dinitrosyl- [3] diiron complexes, were found to be quite useful as functional models for the active site of flavodiiron nitric oxide reductases (FNORs) [4]. FNORs catalyze the two electron reduction of NO to N2O and help the pathogenic bacteria to survive the immune defense response of mammals. Near quantitative generation of N2O upon chemical/electrochemical reduction of these two model complexes have been demonstrated and the mechanisms for such NO reduction processes have been established. Furthermore, in order to check the reactivity of NO with hydrosulfide, a representative diiron(II)-hydrosulfide complex [5] was allowed to react with NO, which yielded a unique monohydrosulfido dinitrosyl diiron(II) compound. The latter compound has been shown to produce N2O following a semireduction mechanism where the coordinated hydrosulfide acts as a spectator ligand. [6]

References:

1. Pal, N.; Majumdar, A. Inorg. Chem. 2016, 55, 3181-3191 2. Jana, M.; Pal, N.; White, C. J.; Kupper, C.; Meyer, F.; Lehnert, N.; Majumdar A.

J. Am. Chem. Soc. 2017, 139, 14380-14383 3. Jana, M.; White, C. J.; Pal, N.; Demeshko, S.; Cordes (née Kupper), C.; Meyer, F.; Lehnert, N.; Majumdar, A. J.

Am. Chem. Soc. 2020, 142, 6600-6616 4. Khatua, S.; Majumdar, A. J. Inorg. Biochem. 2015, 142, 145-153 5. Pal, N.; Majumdar, A. Dalton Trans. 2019, 48, 5903-5908 6. Pal, N.; White, C. J.; Demeshko, S.; Meyer, F.; Lehnert, N.; Majumdar, A. Work under progress


Structure of the Hydrated Proton at the Membrane Interfaces: Vibrational Sum Frequency Generation Study

Prashant Chandra Singh


The understanding of the structure of hydrated proton at the membrane interface is of utter importance due to its involvement in the bioenergetic process of mostly all the organisms. Herein, the structure of hydrated proton at the membrane interface has been investigated by measuring the vibrational sum frequency generated (VSFG) spectra of negatively charged and zwitterionic lipids in the presence of different concentrations of HCl. It has been found that the hydrated proton provides a broad VSFG signal in the range of 2500-2800 cm-1 along with a distinct sharp feature ~2720 cm-1 suggesting the presence of Eigen like hydrated proton at the negatively charged and zwitterionic lipid interfaces. The presence of the hydrated proton near to the head group of negatively charged and zwitterionic lipid interfaces decreases the overall ordering of the hydrocarbon chain of both lipids by modulating the gauche defect and orientational ordering.

References:

(1) Zhang, J.; Unwin, P. R., Proton Diffusion at Phospholipid Assemblies. J. Am. Chem. Soc. 2002, 124 (10), 2379-2383. (2) Fournier, J. A.; Carpenter, W. B.; Lewis, N. H. C.; Tokmakoff, A., Broadband 2D IR spectroscopy reveals dominant asymmetric H5O2+ proton hydration structures in acid solutions. Nat. Chem. 2018, 10 (9), 932-937. (3) Wolke, C. T.; Fournier, J. A.; Dzugan, L. C.; Fagiani, M. R.; Odbadrakh, T. T.; Knorke, H.; Jordan, K. D.; McCoy, A. B.; Asmis, K. R.; Johnson, M. A., Spectroscopic snapshots of the proton-transfer mechanism in water. Science 2016, 354 (6316), 1131.

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