Near-infrared Fourier transform Raman and conventional Raman studies of calf gamma-crystallins in the lyophilized state and in solution

Abstract

We present in this report a detailed structural study of calf gamma-crystallins both in the solid state and in solution by the newly developed technique of near-infrared (IR) Fourier transform (FT)-Raman spectroscopy as well as by the conventional Raman method. In comparison with conventional laser Raman spectroscopy, the near-IR FT-Raman approach exhibits several attractive features such as fluorescence rejection capability, frequency accuracy, and the FT's multiplex and throughput advantages. These distinct characteristics combined form the basis for the particular suitability of FT-Raman in crystallin structural analysis and elucidation. We have thus obtained evidence in support of the view that native calf gamma-II crystallin does not contain a disulfide bond either in the lyophilized state or in solution. In addition, conventional Raman spectra are examined for all four gamma-crystallin fractions. gamma-S, gamma-II, gamma-III, and gamma-IV, and the results indicate a high degree of structural similarities among them. It is also found that the sulfhydryl groups in all four gamma-crystallins are highly resistant to air oxidation and are capable of maintaining their reduced state during isolation in the absence of added reductants or such chelating agents as EDTA.

A Comparison of the Environment of Thiol Groups in Bovine and Human γ Crystallins Using Raman Spectroscopy

“…All three spectra are characterized by the ±SH Raman doublet typical of the g crystallins. This doublet is asymmetrical, with a main band around 2580 cm À1 and a lowerfrequency shoulder near 2560 cm À1 , as reported earlier by us and by others for several bovine g crystallins (Pande et al, 1989(Pande et al, , 1991Chen et al, 1991). While the overall ±SH band pro®les for the three proteins appear to be nearly identical, the area under each pro®le scales exactly with the number of cysteine residues in the corresponding protein.…”

Effect of acetic acid deamidation‐induced modification on functional and nutritional properties and conformation of wheat gluten

“…Disulfide bonds play an important role in protein unfolding and assembly. Chen et al 26 reported that Raman spectroscopy was sensitive enough to detect the redox properties of sulfhydryl groups in lens crystallins. As can be seen in Fig.…”

Influence of Soy Aglycon Isoflavones on Bone-Related Traits and Lens Protein Characteristics of Ovariectomized Rats and Bioactivity Performance of Osteoprogenitor Cells

“…Lens proteins may progressly show conspicuous changes during aging and increase water-insoluble protein aggregation as a result of continuous oxidation of the sulfhydryl groups to form disulfide bonds. Spectroscopic studies of eye lens proteins have proved that Raman spectroscopy is capable of detecting directly the formation of disulfide bonds and may serve as a noninvasive tool to monitor lens development ( , ). In this study, the HPLC proteins including high-molecular-weight (HMW) proteins and various crystallins () have been resolved and are shown in Figure .…”

“…The lens is a lifelong growing organ with no shedding of cellular elements and continuous deposits of the posttranslationally altered proteins in the nucleus and newly synthesized proteins in the cortex. Lens proteins might progressively show conspicuous changes during aging and increase water-insoluble proteins as aggregates resulting from oxidation of sulfhydryl groups to disulfide bonds ( , ). Changes of the sulfhydryl groups could be monitored by Raman spectroscopy.…”