Recognition of single- and double-stranded oligonucleotides by bovine serum albumin via nonspecific interactions.
The complexes formed by bovine serum albumin (BSA) with single-stranded oligonucleotide (ss-oligo) or double-stranded oligonucleotide (ds-oligo) were investigated by laser light scattering, zeta potential analysis, and atomic force microscopy. It was found that BSA was able to recognize ss-oligo and ds-oligo upon forming complexes in HCOOH-HCOONa buffer at pH 3.0. When oligonucleotide was added dropwise to BSA, BSA formed a complex with ss-oligo but not with ds-oligo in the studied charge ratio. When BSA was added to oligonucleotides, BSA formed complexes with both ss-oligo and ds-oligo but via different paths: the BSA/ds-oligo underwent two processes, heavy precipitation followed by reentry, with increasing BSA/oligo charge ratio, whereas BSA/ss-oligo underwent only aggregation process, but with a charge reversal occurred at BSA/oligo charge ratio about 0.1. Moreover, the complex formed by BSA and ds-oligo showed a kinetics much slower than that of BSA and ss-oligo. We attributed the big difference upon complexation to the physical nature of oligonucleotides as well as the conformational change of BSA under severe conditions. The differentiation of ss-oligo from ds-oligo by BSA via nonspecific interactions gained insight in the recognition of DNA or RNA by specific protein (enzyme) under physiological conditions.
Xia
Yuqiong
Y
Beijing National Laboratory for Molecular Sciences and the Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China 100871.
Chen
Erqiang
E
Liang
Dehai
D
D000818:Animals; D002417:Cattle; D018625:Microscopy, Atomic Force; D009841:Oligonucleotides / Q000737:chemistry*; D010316:Particle Size; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013379:Substrate Specificity; D013499:Surface Properties
D009841:Oligonucleotides; D012710:Serum Albumin, Bovine