Venanzi Mariano, Bocchinfuso Gianfranco, Gatto Emanuela, Palleschi Antonio, Stella Lorenzo, Formaggio Fernando, Toniolo Claudio
Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica, Rome, Italy.
Chembiochem. 2009 Jan 5;10(1):91-7. doi: 10.1002/cbic.200800617.
The metal ion binding properties of two fluorescent analogues of trichogin GA IV, which is a natural undecapeptide showing significant antimicrobial activity, were studied by circular dichroism, time-resolved optical spectroscopy, and molecular mechanics calculations. Binding of Ca(II) and Gd(III) to the peptides investigated was shown to promote a structural transition from highly helical conformations to folded structures characterized by formation of a loop that embedded the metal ion. Time-resolved spectroscopy revealed that peptide dynamics is also remarkably affected by ion binding: peptide-backbone motions slowed down to the microsecond time scale. Finally, molecular mechanics calculations emphasized the role of the central Gly5-Gly6 motif, which allowed for the twisting of the peptide segment that gave rise to the formation of the binding cavity.
曲古抑菌素GA IV是一种具有显著抗菌活性的天然十一肽，对其两种荧光类似物的金属离子结合特性进行了研究，采用了圆二色性、时间分辨光谱和分子力学计算方法。研究表明，Ca(II)和Gd(III)与所研究的肽结合会促进结构从高度螺旋构象转变为折叠结构，其特征是形成了一个嵌入金属离子的环。时间分辨光谱显示，离子结合也显著影响肽的动力学：肽主链运动减慢至微秒时间尺度。最后，分子力学计算强调了中心Gly5-Gly6基序的作用，它使得肽段发生扭曲，从而形成了结合腔。
