Protein-encapsulated gold cluster aggregates: the case of lysozyme.
We report the evolution and confinement of atomically precise and luminescent gold clusters in a small protein, lysozyme (Lyz) using detailed mass spectrometric (MS) and other spectroscopic investigations. A maximum of 12 Au(0) species could be bound to a single Lyz molecule irrespective of the molar ratio of Lyz : Au(3+) used for cluster growth. The cluster-encapsulated protein also forms aggregates similar to the parent protein. Time dependent studies reveal the emergence of free protein and the redistribution of detached Au atoms, at specific Lyz to Au(3+) molar ratios, as a function of incubation time, proposing inter-protein metal ion transfer. The results are in agreement with the studies of inter-protein metal transfer during cluster growth in similar systems. We believe that this study provides new insights into the growth of clusters in smaller proteins.
DST Unit of Nanoscience, Department of Chemistry, Indian Institute of Technology Madras, Chennai-600036, India.
Ananya
A
Baksi
Paulrajpillai Lourdu
PL
Xavier
Kamalesh
K
Chaudhari
N
N
Goswami
S K
SK
Pal
T
T
Pradeep
D002942:Circular Dichroism; D019281:Dimerization; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D045663:Quantum Dots; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D006046:Gold; D009113:Muramidase