Dr. Karunakar Kar

BIOPHYSICAL AND BIOMATERIALS RESEARCH LAB

310, School of Life Sciences,

Jawaharlal Nehru University,

New Delhi-110067, INDIA;

email: karunakarkar@gmail.com,

kkar@mail.jnu.ac.in

phone: +91-1126704517; (office),

ORCID | Research Gate | Google Scholar | TWItter X |

RESEARCH AREA

We are curious to know how simple aromatic molecules underdo self-assembly or co-assembly and yield defined nanostructures. What is the mechanism of self-assembly/co-assembly? How is this inherent property of aromatic metabolites linked to the In-born Metabolic diseases? How can we use this property as a tool to design novel catalytic nanomaterials? We work to find clear answers to these important questions by using different experimental and computational approaches. Since the process of protein amyloid aggregation is linked to a multitude of amyloid-linked diseases including neuronal and non-neuronal problems, finding effective and biocompatible inhibitors against such aggregation process could be beneficial. Targeting the aggregation prone residues of proteins may perhaps work as an effective strategy to prevent the onset of fibril assembly of proteins. We have synthesized uniform sized, thermostable gold and silver nanoparticle surface-functionalized with selected natural compounds, to target amyloid fibril formation of disease linked proteins. The findings of this work may help in the understanding of the mechanism of amyloid linked pathologies and for the development of nanoparticle-based formulations to prevent medical problems linked to protein aggregation.

Current Research Projects:

1- Self-assembly of metabolites into amyloid-like nanostructures: mechanism of In born metabolic disorders

2. Natural compound based nanoformulations to target amyloid-linked diseases.

3. Collagen peptide based, rationally engineered nanomaterials,

Genesis of neurotoxic hybrid nanofibers from the coassembly of aromatic amino acids. Three aromatic amino acids (Tyr, Trp, and Phe) undergo a spontaneous coassembly process, driven by noncovalent interactions, and yield neurotoxic and cross-seeding-competent hybrid nanofibers [Kar et al. ACS Applied Materials & Interfaces 13 (31), 36722-36736]

Single metabolites: serotonin, dopamine, tryptophan and histidine can self-assemble into cytotoxic nanostructures and show diverse damaging effects (Necrosis, apoptosis, ROS generation, DNA damage, hemolysis etc.) [Kar et al. ACS Applied Materials & Interfaces; ACS Nano 2019, 2024, Nanoscale, ACS Chemical Neuroscience)

TEACHING

MSc- Courses

Ph.D. courses:

LS 644A Biomacromolecules in Bioengineering

LAB MEMBERS

current Lab MeMbers

Dr. Kailash Prasad Prajapati:

PhD.

MSc- School of Life Sciences, JNU New Delhi

Thesis: Self-assembly of aromatic metabolites into amyloid like nanostructures and their effect on proteins and cells

Dr. Masihuzzaman Ansari:

PhD.

MSc- School of Life Sciences, Tezpur University, Assam.

Thesis: Understanding the structural and cytotoxic properties of co-assembly generated multicomponent amyloids

Shikha Mittal

PhD. Final year, MSc- Chaudhary Charan Singh University, Meerut

Thesis: Effect selected of natural compounds on amyloid aggregation of proteins

Om Prakash

PhD. Final year, MSc- School of Life Sciences, JNU

Thesis: Natural compound based metallic nanoparticles for targetting amyloid aggregation of proteins.

Prasant

MSc- Dissertation

Project: Amyloid Cross-seeding in cells

Lab Alumni

Dr. Bibin G. Anand.

Ph.D. 2017;

Thesis title: "Nanoparticle based inhibitors to target protein aggregation"

Dr. Kriti Dubey

PhD. 2017;

Thesis title: "Biophysical approach to develop potential inhibitors against protein aggregation "

Ms. Paramita Chaudhuri MPhil 2019;

Thesis title: "Study of the effect of homogeneous and heterogeneous seeds during of amyloid cross-seeding of proteins."

Ms. Kajal Joshi

M.Sc Dissertation 2022;

Thesis title: "Effect of Cu ions on Insulin amyloid aggregation"

Ms. Vartika Gupta MSc Dissertation 2022;

Thesis title: "Aspartame nantstructure as a cross-seeding agent for type II diabetes linked Insulin"

Ms. Shraddha Mishra MSc Dissertation 2022;

Thesis title: "Phase change in peptidase Papain via temperature switch"

Postdoc and Research Fellows

Dr. Pratishtha Singh (ICMR RA)

Sobha Ahlawat (SERB- JRF)

MSc/Dissertation Students.

Akhilesh

Deepak Kumar Yadav

Harshi

Sharmeen

Shradha Mishra

Vartika Gupta

Kajal Joshi

Swati Patidar

Vaishali Bhati

Harsha

Pranjali Yadav

PUBLICATIONS (selected)

M Ansari, KP Prajapati, S Mittal, S Mishra, V Gupta, BG Anand, K Kar. High-low temperature switch induces formation of catalytic and cytotoxic papain amyloid aggregates. Food Chemistry, 2025, 479, 143657 [Impact Factor = 9.8] <link>-
Prajapati K.P., Mittal, S., Ansari, M., Mishra, N., Mahato, O.P., Tiku, A.B, Anand, B.G.*, Kar, K*. Structural Conversion of Serotonin into Amyloid-like Nanoassemblies Conceptualizes an Unexplored Neurotoxicity Risk. ACS Nano. 2024, 18, 50, 34044-34062. [Impact Factor = 16.0] <link>-
Mittal, S., Prajapati, K.P., Ansari M, Joshi, K., Mishra, N., Anand, B.G.* Kar K.* Cu (II) specifically disassembles insulin amyloid nanostructures via direct interaction with cross-β fibrils. Nano Letters 2024, 24, 32, 9784–9792 [Impact Factor = 11.6] <link>-(Front Cover Article)
Ansari M., Prajapati, K.P., Mittal S., Anand, B.G,, Mishra, N., Anand, B., Kar, K.* Sequence Independent Rapid Co-aggregation of Proteins: Possible Role of Conformational Complementarity: Biochemistry 2024, 63, 22, 2977–2989 [Impact factor 3.0] <link>-(Front Cover Article)
Roy S., Ramanan, V., Arunagiri, S., Mishra, N., Bhatia, A., Shejale, K.P., Prakapati, K.P., Kar K.* and Anand, B.G.* Insight into the Intricacies of Lysozyme Aggregation: Implications for Designing Anti-Amyloid Therapies in Diverse Pathological Conditions. Advances in Colloid and Interface Science 2024 Sep:331:103205.[Impact Factor = 19.3] <link>
Prajapati K.P., Mittal S., Ansari M., Mahato O.P., Bharati S., Singh A.P., Ahlawat S., Tiku A.B., Anand B.G., Kar K*. Pleiotropic Nanostructures Built from l-Histidine Show Biologically Relevant Multicatalytic Activities. ACS Appl Mater Interfaces. 2024 Apr 17;16(15):18268-18284. [Impact Factor =10] <link>-
Ansari M., Prajapati1, K.P., Anand, B.G., Chaudhuri, P., Shikha Mittal, Kar, K.* Construction of Chemoreactive Heterogeneous Nanofibers Through Strategic Co-assembly of Different Proteins. Materials Today Nano 2023, 22, 100317 [Impact Factor =13.5] <link>-

Anand, B.G., Prajapati, K.P., Dubey, K., Ahamad, N., Shekhawat, D.S., Rath, P.C., Joseph, G.K., Kar, K.* Self-Assembly of Artificial Sweetener Aspartame Yields Amyloid-Like Cytotoxic Nanostructures. ACS Nano. 2019; 13: 6033-6049. [Impact Factor = 16.0] <link>

Chaudhuri, P., Prajapati, K.P., Dubey, K., Anand, B.G., Kar, K.*Amyloid cross-seeding raises new dimensions to understanding of amyloidogenesis mechanism. Ageing Research Reviews. 2019, 56:100937; pp1-18. [Impact Factor = 12.5] <link>

Misra, P., Kodali, R., Chemuru, S., Kar, K., Wetzel, R. Rapid α-oligomer formation mediated by the Aβ C-terminus initiates an amyloid assembly pathway. Nature Communication, 2016; 7:12419. [Impact Factor = 17.7] <link>

Kar, K., Jayaraman, M., Sahoo, B., Kodali, R., Wetzel, R., Critical nucleus size for disease-related polyglutamine aggregation is repeat length dependent. Nature Structural & Molecular Biology, 2011; 18, 328-336 [Impact Factor = 18.4]- <link> highlighted in the cover page and in Faculty1000

Hoop, C.L., Lin, H.K., Kar, K., Magyarfalvi, G., Lamley, J.M., Boatz, J.C., Lewandowski, J.R., Wetzel, R., van der Wel, P.C. Huntingtin exon 1 fibrils feature an interdigitated β-hairpin–based polyglutamine core. Proceedings of the National Academy of Sciences 2016; 113(6):1546-1551 [Impact Factor = 12.8] <link> News [EUREKALERT; Science Daily; Huntington's Disease News; ]

Prajapati. K.P., Anand, B.G., Ansari, M., Temgire, M., Tiku, A.B., Kar, K.* Tryptophan Self-assembly Yields Cytotoxic Nanofibers Containing Amyloid-Mimicking and Cross-Seeding Competent conformers. Nanoscale 2022, 14,16270-16285 [impact Factor = 8.3] <link>

Prajapati, K.P., Ansari M., Yadav D., K., Mittal, S., Anand, B.G., Kar, K.*A Robust Yet Simple Method to Generate Fluorescent Amyloid Nanofibers , Journal of Materials Chemistry B, 2023, 11, 8765-8774 [impact Factor= 7.5] <link>

Kar, K., Hoop, C., Baker, M.A., Lengyel, G., Kodali, R., van der Wel, P., Horne, S., Wetzel, R., Backbone engineering within a latent β-hairpin structure to design inhibitors of polyglutamine amyloid formation Journal of Molecular Biology, 2017, 429:308-323, [Impact Factor = 5.5] <link>
Kar, K., Arduini, I., Drombosky, K.W., van der Wel, P.C., Wetzel, R. D-polyglutamine amyloid recruits L-polyglutamine monomers and kills cells. Journal of Molecular Biology, 2014; 426:816-829 [Impact Factor = 5.5]

Kar, K., Amin, P., Bryan, M.A., Persikov, A.V., Mohs, A., Wang, Y.H., Brodsky, B., Self- association of collagen triple helical peptides into higher order structures. Journal of Biological Chemistry, 2006; 281:33283-33290. [Impact Factor =5.2] <link> Full Text