The structure and dynamics of an antigen-antibody complex are monitored by circular dichroism (CD) spectroscopy, fluorescence correlation spectroscopy (FCS) and single molecule FRET (smFRET). In this work, the antigen is enhanced GFP (EGFP) and the antibody is anti-EGFP VHH-His6. From FCS measurements, the hydrodynamic radius (rH) of EGFP and its antibody (VHH-His6) is found to be 24 ± 2 Å and 18 ± 2 Å, respectively. For the antigen-antibody complex (EGFP:anti-EGFP VHH-His6), rH is 41 ± 3 Å. CD spectra indicate that the addition of guanidium hydrochloride (GdnHCl) causes unfolding of the antigen, its antibody and their complex, and a consequent increase in size is observed from FCS data. smFRET between EGFP (donor, D) and Alexa 594 (acceptor, A) bound to anti-EGFP VHH-His6 reveals a time dependent fluctuation in donor-acceptor distances. This suggests that the structure of the antigen-antibody complex is dynamic in nature and is not rigid. This journal is © the Owner Societies 2015.

Surajit Ghosh

Department of Bioscience & Bioengineering

IIT Jodhpur

D. Bhunia

R. Chowdhury

K. Bhattacharyya

&ldquo;IIT Jodhpur is committed to impart quality education to facilitate the creation of qualified, competent and responsible human resources to meet the emerging technological challenges of the world. It is working towards creating an equitable learning platform that is positive, accessible and effective in the face of the modern societal and scientific advancements.

Flexibility in curriculum, in all its academic programs, encompassing elements of teaching, research, creativity, innovation and entrepreneurship is the most unique feature of IIT Jodhpur. The Department of Science and Technology (DST), under the National Mission on Cyber Physical Systems, has identified IIT Jodhpur as a Technology &amp; Innovation Hub in the area of Augmented Reality and Virtual Reality. The institute has also been nominated as the coordinator for the Jodhpur City and Knowledge Cluster by the Office of Principal Scientific Adviser, Government of India.

The sprawling 852-acre IIT Jodhpur campus is a majestic tribute to the deep-rooted diverse cultural heritage of the region. The campus is an architectural masterpiece, which is slated to become an international exemplar of sustainability with net-zero energy, and advanced water and waste management strategies.&rdquo;

Journal	Data powered by TypesetPhysical Chemistry Chemical Physics
Publisher	Data powered by TypesetRoyal Society of Chemistry
ISSN	14639076