CAJ | 학술논문

左氧氟沙星（L V FX ）是临床上普遍使用的一种抗生素，对革兰氏阳性菌及革兰氏阴性菌引起的各种感染都有一定的作用。人血清白蛋白（HSA）是血液循环系统中最丰富的运输蛋白，能与多种内源及外源性物质结合，起着储存和转运的作用。因此详细研究LVFX与HSA间的相互作用对了解LVFX的药代动力学行为具有重要意义。运用光谱法和分子对接模拟技术研究左氧氟沙星和人血清白蛋白的相互作用。结果表明，LVFX对 HSA的荧光淬灭作用为形成复合物导致的静态猝灭，结合常数为9.44×104 L · mol-1（294 K）和2.72×104 L · mol-1（310 K），结合位点数均为1，两者间的主要作用力为氢键和范德华力。取代实验表明，LVFX在 HSA的Site Ⅰ，Ⅱ A 子域上有一个结合位点。根据 F?rster理论得到的 LVFX和色氨酸（T rp）残基间的结合距离为3.66 nm ，这一结果与分子对接模拟技术得到的结果相一致。紫外差谱，三维荧光光谱和红外光谱都进一步表明 LVFX能够改变 HSA的结构。采用傅里叶变换红外光谱法对 LVFX与HSA作用前后 HSA二级结构的变化进行了定量分析，结果表明，当加入LVFX后HSA的α-螺旋结构有所降低，β-折叠结构、β-转角结构和无规则卷曲有所上升，说明LVFX能使HSA的二级结构变得松散。
좌양불사성（L V FX ）시림상상보편사용적일충항생소，대혁란씨양성균급혁란씨음성균인기적각충감염도유일정적작용。인혈청백단백（HSA）시혈액순배계통중최봉부적운수단백，능여다충내원급외원성물질결합，기착저존화전운적작용。인차상세연구LVFX여HSA간적상호작용대료해LVFX적약대동역학행위구유중요의의。운용광보법화분자대접모의기술연구좌양불사성화인혈청백단백적상호작용。결과표명，LVFX대 HSA적형광쉬멸작용위형성복합물도치적정태졸멸，결합상수위9.44×104 L · mol-1（294 K）화2.72×104 L · mol-1（310 K），결합위점수균위1，량자간적주요작용력위경건화범덕화력。취대실험표명，LVFX재 HSA적Site Ⅰ，Ⅱ A 자역상유일개결합위점。근거 F?rster이론득도적 LVFX화색안산（T rp）잔기간적결합거리위3.66 nm ，저일결과여분자대접모의기술득도적결과상일치。자외차보，삼유형광광보화홍외광보도진일보표명 LVFX능구개변 HSA적결구。채용부리협변환홍외광보법대 LVFX여HSA작용전후 HSA이급결구적변화진행료정량분석，결과표명，당가입LVFX후HSA적α-라선결구유소강저，β-절첩결구、β-전각결구화무규칙권곡유소상승，설명LVFX능사HSA적이급결구변득송산。
Levofloxacin (LVFX) is widely used in clinical treatment due to it has a broad spectrum of in vitro activity against Gram-positive and Gram-negative bacteria .Human serum albumin (HSA) is the most abundant protein in plasma and constitutes approximately half of the protein founds in human blood .And more than 90% of the drugs used in people are bound to HSA .So it is commonly used for the investigation of drug-serum albumin interaction because the binding will significantly influence the ab-sorption ,distribution ,metabolism excretion ,stability and toxicity of the drugs .Therefore ,detailed investigating the interaction of LVFX with HSA is very important to understand the pharmacokinetic behavior of the LVFX .In this paper ,the interaction of LVFX and HSA has been studied fluorescence ,UV ,Fourier transform infrared (FT-IR) and molecular modeling method .The results indicated that LVFX induced the intrinsic fluorescence quenching of HSA though a static quenching procedure ,and the effective binding constants (Ka ) were calculated to be 9.44 × 104 L · mol-1 (294 K) and 2.74 × 104 L · mol-1 (310 K) by used of the Stern-Volmer equation .According to the Vant’s Hoff equation ,the reaction was characterized by negative enthalpy (ΔH=-59.00 kJ · mol-1 ) and negative entropy (ΔS= -105.38 J · mol-1 · K -1 ) ,indicated that the predominant forces in the LVFX-HSA complex were hydrogen bonding and van der Waals forces .By displacement measurements ,the specific binding of LVFX in the vicinity of Site Ⅰ of HSA was clarified .The binding distance of 3.66 nm between Trp214 and HSA was obtained by the F?rster theory on resonance energy transfer .Furthermore ,the binding details between LVFX and HSA were further con-firmed by molecular docking studies ,which were consistent with the experimental results .The alternations of protein secondary structure were calculated from FT-IR spectra .Upon formation of LVFX-HSA complexes ,the amount of α-helical structures were decrease ,but the numbers of β-sheet structures ,β-turn structures and random structures were increase ,respectively .This result indicated that LVFX induced unfolding of the polypeptides of HSA .