采用SDS研究泥蚶血红蛋白(Tg-HbⅡ)具有过氧化物酶及抗菌活性的结构基础OA北大核心CSTPCD

Hemoglobin Ⅱ from Tegillarca granosa(Tg-HbⅡ)possesses oxygen-carrying capabilities as well as peroxidase and antibacterial activities.In this study,we examined the effects of sodium dodecyl sulfate(SDS)on the structure,peroxidase activity,and antibacterial activity of Tg-HbⅡ using spectrophotometric,spectroscopic,and molecular docking techniques.Moreover,we explored the structural basis of the peroxidase activity of Tg-HbⅡand its antibacterial activities.The results revealed that the hydrophobic alkyl long chains of SDS could integrate into the heme pocket of Tg-HbⅡ,forming hydrogen bonds with the proximal His104.This interaction resulted in the breaking of the coordination bond between heme iron and His104,leading to a decrease and shift in the Soret band absorption peak of Tg-HbⅡ.Additionally,SDS could form hydrophobic interactions with the amino acids in the heme pocket,inducing alterations in the original structure and exposing some hydrophobic amino acids.This re-sulted in an enhanced exogenous fluorescence intensity and a redshift of the maximum emission wavelength.SDS demonstrated an inhibitory effect on the peroxidase activity of Tg-HbⅡ.At 2 mmol·L-1 of SDS concentration,the enzymatic activity of Tg-HbⅡ was only 20％of that of the original,and the antibacterial activity against Bacillus subtilis was lost in agar diffusion experiments.These results indicated that SDS inhibited the peroxidase activity of Tg-HbⅡ by disrupting the internal structure of the heme pocket,consequently leading to the loss of its antibacterial activity.The heme hydrophobic pocket emerged as a key structure for the peroxidase and antibacterial activities of Tg-HbⅡ.This study lays the foundation for future studies on the antibacterial mechanism of Tg-HbⅡ.