Department of Chemistry, DePaul University, Chicago, IL 60604-6116, United States of America.
Beckman Institute, California Institute of Technology, Pasadena, CA 91125, United States of America.
J Inorg Biochem. 2020 Jul;208:111091. doi: 10.1016/j.jinorgbio.2020.111091. Epub 2020 May 11.
We use crystallographic data for four helical iron proteins (cytochrome c-b, cytochrome c', sperm whale myoglobin, human cytoglobin) to calculate radial and angular signatures as each unfolds from the native state stepwise though four unfolded states. From these data we construct an angle phase diagram to display the evolution of each protein from its native state; and, in turn, the phase diagram is used to construct a funneled angle landscape for comparison with the topography of its folding energy landscape. We quantify the departure of individual helical and turning regions from the areal, angular profile of corresponding regions of the native state. This procedure allows us to identify the similarities and differences among individual helical and turning regions in the early stages of unfolding of the four helical heme proteins.
我们使用四个螺旋铁蛋白（细胞色素 c-b、细胞色素 c'、抹香鲸肌红蛋白、人细胞球蛋白）的晶体学数据，计算每个蛋白从天然状态逐步展开到四个无规则状态时的径向和角向特征。根据这些数据，我们构建了一个角度相图来展示每个蛋白从天然状态的演变；反过来，相图又被用来构建一个有向角的景观，以便与它的折叠能量景观的地形进行比较。我们量化了单个螺旋和转角区域与天然状态对应区域的面积、角度轮廓的偏离程度。通过这个过程，我们可以识别出四个螺旋血红素蛋白在展开的早期阶段中单个螺旋和转角区域之间的相似性和差异性。
