%0 journal article
%@ 1525-7797
%A Zou, A., Liu, J., Haramus, V.M., Zheng, K., Willumeit, R., Mu, B.

%D 2010
%J Biomacromolecules
%N 3
%P 593-599 
%R doi:10.1021/bm9011453
%T Interaction between the Natural Lipopeptide [Glu1, Asp5] Surfactin-C15 and Hemoglobin in Aqueous Solution
%U https://doi.org/10.1021/bm9011453
3 
%X The interaction between natural lipopeptide [Glu1, Asp5] surfactin-C15 (surfactin) and hemoglobin (Hb) has been studied. Surface tension measurements show that the critical micelle concentration (cmc) of surfactin increases from 1.54 × 10−5 to 3.86 × 10−5 mol/L with Hb. The UV spectra display that the effect of surfactin on Hb exhibits strong concentration-dependent fashion and the aquometHb convert to hemichrome at high surfactin concentration. Small-angle neutron scattering (SANS) and freeze-fracture transmission electron microscopy (FF-TEM) measurements show that surfactin result in the formation of a fractal structure representing a “necklace model” of micelle-like clusters randomly distributed along the protein polypeptide chain at high surfactin concentration. Far-UV circular dichroism (CD) results confirmed that surfactin can disrupt the helical structure of protein at high concentrations, although the enhanced native-like behavior of protein by low concentration of surfactin was observed. The microenvironment change around Phe amino residues and disulfide bonds of Hb was obtained from near-UV CD spectra.