Impact of the enfuvirtide resistance mutation N43D and the associated baseline polymorphism E137K on peptide sensitivity and six-helix bundle structure
Impact of the enfuvirtide resistance mutation N43D and the associated baseline polymorphism E137K on peptide sensitivity and six-helix bundle structure
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DOI：
10.1021/bi702509d
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发表时间：
2008-06-24
期刊：
影响因子：
2.9
通讯作者：
Dwyer, John J.
中科院分区：
文献类型：
--
作者：
Bai, Xuefang;Wilson, Karen L.;Dwyer, John J.
恩夫韦肽（ENF）是第一个被批准用于临床的人类免疫缺陷病毒1型（HIV-1）融合抑制剂，通过与gp 41七肽重复序列1（HR 1）结合并阻止其与病毒HR 2区域相互作用而发挥作用。治疗后出现的对ENF的耐药性已被映射到HR 1内的残基，这些突变降低了其对ENF的敏感性，并可能降低病毒适应性和发病机制，尽管这些作用的机制尚不清楚。N43 D是一种常见的ENF抗性突变，在体外试验中发现其抗病毒活性增加5-50倍。我们将这种突变引入肽模型，并通过圆二色性和X射线晶体学确定这种突变的影响。我们发现，突变导致六螺旋束的热稳定性降低，并导致HR 1-HR 2界面发生显着变化，包括HR 2螺旋度的损失。这些数据形成了ENF灵敏度和六螺旋束稳定性降低的机制基础。E137 K多态性，通常存在于基线的患者谁开发N43 D，部分补偿稳定性的损失，我们表明，这些残基可能形成一个离子对。这些数据形成了理解耐药突变对病毒适应性和发病机制的影响的框架，并为开发新型融合抑制剂肽提供了途径。
Enfuvirtide (ENF), the first human immunodeficiency virus type 1 (HIV-1) fusion inhibitor approved for clinical use, acts by binding to gp41 heptad repeat 1 (HR1) and preventing its interaction with the viral HR2 region. Treatment-emergent resistance to ENF has been mapped to residues within HR1, and these mutations decrease its susceptibility to ENF and may reduce viral fitness and pathogenesis, although the mechanism for these effects is not clear. N43D, a common ENF resistance mutation, was found in in vitro assays to cause a 5-50-fold in antiviral activity. We introduced this mutation into peptide models and determined the impact of this mutation by circular dichroism and X-ray crystallography. We find that the mutation results in a decrease in the thermal stability of the six-helix bundle and causes a significant change in the HR1-HR2 interface, including a loss of HR2 helicity. These data form a mechanistic basis for the decrease in ENF sensitivity and six-helix bundle stability. The E137K polymorphism, generally present at baseline in patients who develop N43D, partially compensates for the loss of stability, and we show that these residues likely form an ion pair. These data form a framework for understanding the impact of resistance mutations on viral fitness and pathogenesis and provide a pathway for the development of novel fusion inhibitor peptides.