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First principles study of the optical response of Au 8 cluster conjugated with methionine, tryptophan, and tryptophyl‐methionine dipeptide
Author(s) -
Abdalmoneam Marwa H.,
Saikia Nabanita,
Abd ElMageed H.R.,
Pandey Ravindra
Publication year - 2021
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.4201
Subject(s) - chemistry , dipeptide , conjugated system , indole test , tryptophan , chromophore , methionine , amino acid , fluorescence , density functional theory , thioether , photochemistry , stereochemistry , combinatorial chemistry , organic chemistry , biochemistry , computational chemistry , polymer , physics , quantum mechanics
Abstract Bioconjugated complexes of the Au clusters are shown to demonstrate unique electronic properties and exceptional tunable optical features for applications in health‐related areas including cell imaging and target‐specific drug delivery. To establish the relationship between the optical response and the nature of interaction in such complexes, we consider the cases of the representative amino acids, L‐methionine, L‐tryptophan, and L‐tryptophyl‐L‐methionine dipeptide conjugated with Au 8 cluster. The results based on time‐dependent density functional theory find the near‐ultraviolet (UV) absorption of the complexes is dominated by the cluster, though site‐specific interactions through the indole chromophore or thioether side chains provide their signature responses in the optical spectra. Under physiological conditions, the predicted optical recognition of specific bonds formed between Au 8 cluster and amino acids can then be exploited in the design of functional fluorescent bio‐labels for biochemical sensing and detection of thiols, polypeptides, proteins, and nucleic acids at nanoscale.