Phytolacca americana lectin (Pa-2; pokeweed mitogen): an intrinsically unordered protein and its conversion into partial order at low pH. Issue 2 (23rd November 2009)

• Record Type: Journal Article
• Authors: Ahmad, Ejaz; Kamranur Rahman, Shah; Masood Khan, Javed; Varshney, Ankita; Hasan Khan, Rizwan
• Is Part Of: Bioscience reports. Volume 30:Issue 2(2010)
• Page Start: 125
• Page End: 134
• Publication Date: 2009-11-23
• Subjects: CD -- dynamic light scattering -- hydropathy -- intrinsically unordered protein -- premolten globule state; Molecular biology -- Periodicals; Cytology -- Periodicals; 572.8
• DOI: 10.1042/BSR20090035
• Languages: English
• ISSNs: 0144-8463

Abstract

Abstract : This is the first report of its kind that well demonstrates that a lectin from Phytolacca americana [Pa-2 ( P. americana lectin-2)] can also be intrinsically unordered, based on the results obtained by CD, tryptophan fluorescence, ANS (8-anilinonaphthalene-1-sulfonic acid) binding, acrylamide quenching, DLS (dynamic light scattering) and its amino acid composition database analyses. Pa-2 is an acidic monomeric lectin and acquires random coil conformation at neutral pH without any regular secondary structure. As confirmed by different spectroscopic techniques, on lowering the pH, some secondary structures, predominantly α-helices, are detected by far-UV CD that adopt a marginally stable partially folded collapsed conformation possessing the characteristics of a premolten globule state. It is in accordance with coil–helix transition that is commonly observed when these intrinsically unordered proteins interact with their partner molecules in vivo .