Sincrotrone Trieste S.C.p.A., in Area Science Park, Strada Statale 14, km 163.5, I-34012 Basovizza, Trieste, Italy.
Langmuir. 2010 Jun 1;26(11):8606-13. doi: 10.1021/la904684e.
The adsorption of histidine (His) and three His-derived peptides on Au(111) has been studied by soft X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure spectroscopy (NEXAFS) at the nitrogen and oxygen K edges. The peptides were glycyl-histidine (Gly-His), glycyl-histidine-glycine (Gly-His-Gly), and glycyl-glycyl-histidine (Gly-Gly-His) and were adsorbed at saturated coverage on the Au(111) surface from aqueous solution. Coverages of 1 and 0.5 monolayers (ML) of His were adsorbed by evaporation in vacuum and compared with 1 ML deposited from solution. There were no significant chemical differences between the monolayers deposited in vacuum or from solution. The Au 4f core level shift indicates that a chemisorption rather than a physisorption bond is formed. In both deposited phases, His bonds to the gold surface in anionic form via the imino nitrogen atom of the imidazole ring and the oxygen atoms of the carboxylate group. N and O K-edge NEXAFS indicate that the ring and carboxylate triangle of adsorbed His are tilted at approximately 35 degrees and approximately 27 degrees, respectively, with respect to the Au(111) surface. The peptides bond to the gold surface in a mode similar to the single His molecule, via the imino and carboxylate groups, while the peptide group is at a steep angle to the surface. However, the peptides adsorb with a higher atomic density, consistent with the peptide groups being above the surface. There are also differences between Gly-His-Gly and Gly-Gly-His, implying that the sequence within the peptide has a significant influence on the bonding geometry.
组氨酸（His）及其三种衍生肽在 Au(111) 上的吸附通过软 X 光电子能谱（XPS）和近边 X 射线吸收精细结构光谱（NEXAFS）在氮和氧 K 边进行了研究。这些肽是甘氨酰组氨酸（Gly-His）、甘氨酰组氨酸-甘氨酸（Gly-His-Gly）和甘氨酰-甘氨酰-组氨酸（Gly-Gly-His），并从水溶液中以饱和覆盖度吸附在 Au(111) 表面上。真空蒸发吸附了 1 和 0.5 个单层（ML）His，并与从溶液中沉积的 1 ML 进行了比较。真空沉积或从溶液中沉积的单层之间没有明显的化学差异。Au 4f 芯能级位移表明形成了化学吸附而不是物理吸附键。在这两种沉积相中，His 通过咪唑环的亚氨基氮原子和羧酸盐基团的氧原子以阴离子形式与金表面键合。N 和 O K 边 NEXAFS 表明，吸附 His 的环和羧酸盐三角形相对于 Au(111) 表面分别倾斜约 35 度和 27 度。肽以类似于单个 His 分子的方式通过亚氨基和羧酸盐基团与金表面键合，而肽基团与表面呈陡峭角度。然而，肽以更高的原子密度吸附，与肽基团位于表面上方一致。Gly-His-Gly 和 Gly-Gly-His 之间也存在差异，这表明肽内的序列对键合几何形状有重大影响。
