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Int J Biol Macromol. 2019 Jul 15;133:839-849. doi: 10.1016/j.ijbiomac.2019.04.141. Epub 2019 Apr 22.

The role of G-quadruplex structures of LIGS-generated aptamers R1.2 and R1.3 in IgM specific recognition.

Author information

1
Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, I-80126 Napoli, Italy.
2
Department of Chemistry, City University of New York - Lehman College, 250 Bedford Park Blvd. West, Bronx, New York, NY 10468, USA.
3
Ph.D. Program in Chemistry and Biochemistry, CUNY Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA.
4
Department of Chemistry, City University of New York - Lehman College, 250 Bedford Park Blvd. West, Bronx, New York, NY 10468, USA; Ph.D. Program in Chemistry and Biochemistry, CUNY Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA; Ph.D. Program in Molecular, Cellular and Developmental Biology, CUNY Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA. Electronic address: prabodhika.mallikaratchy@lehman.cuny.edu.
5
Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, I-80126 Napoli, Italy. Electronic address: daniela.montesarchio@unina.it.

Abstract

Exploiting a variant of SELEX called "Ligand-Guided Selection" (LI-GS), we recently identified two novel truncated G-rich aptamers, called R1.2 and R1.3, specific for membrane-bound IgM (mIgM), the hallmark of B cells. Herein, the conformational behaviour of these aptamers has been analysed by multiple biophysical methods. In order to investigate their functional secondary structures, these studies have been carried out in pseudo-physiological buffers mimicking different cellular environments. Both aptamers proved to be highly polymorphic, folding into stable, unimolecular G-quadruplex structures in K+-rich buffers. In turn, in buffered solutions containing Na+/Mg2+ ions, R1.2 and R1.3 formed mainly duplex structures. Remarkably, these aptamers were able to effectively bind mIgM on B-cell lymphoma exclusively in the presence of potassium ions. These findings demonstrate the key role of G-quadruplex folding in the molecular recognition and efficient binding of R1.2 and R1.3 to mIgM expressed in lymphoma and leukemia cells, providing a precious rational basis for the design of effective aptamer-based biosensors potentially useful for the detection of cancer-relevant biomarkers.

KEYWORDS:

Aptamers; G-quadruplex; Membrane-bound IgM

PMID:
31022491
PMCID:
PMC6548653
[Available on 2020-07-15]
DOI:
10.1016/j.ijbiomac.2019.04.141

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