Resonance Raman spectroscopic study of the interaction between Co(II)rrinoids and the ATP:corrinoid adenosyltransferase PduO from Lactobacillus reuteri

Abstract

The human-type ATP:corrinoid adenosyltransferase PduO from Lactobacillus reuteri (LrPduO) catalyzes the adenosylation of Co(II)rrinoids to generate adenosylcobalamin (AdoCbl) or adenosylcobinamide (AdoCbi+). This process requires the formation of “supernucleophilic” Co(I)rrinoid intermediates in the enzyme active site that are properly positioned to abstract the adeonsyl moiety from co-substrate ATP. Previous magnetic circular dichroism (MCD) spectroscopic and X-ray crystallographic analyses revealed that LrPduO achieves the thermodynamically challenging reduction of Co(II)rrinoids by displacing the axial ligand with a non-coordinating phenylalanine residue to produce a four-coordinate species. However, relatively little is currently known about the interaction between the tetradentate equatorial ligand of Co(II)rrinoids (the corrin ring) and the enzyme active site. To address this issue, we have collected resonance Raman (rR) data of Co(II)rrinoids free in solution and bound to the LrPduO active site. The relevant resonance-enhanced vibrational features of the free Co(II)rrinoids are assigned on the basis of rR intensity calculations using density functional theory to establish a suitable framework for interpreting rR spectral changes that occur upon Co(II)rrinoid binding to the LrPduO/ATP complex in terms of structural perturbations of the corrin ring. To complement our rR data, we have also obtained MCD spectra of Co(II)rrinoids bound to LrPduO complexed with the ATP analogue UTP. Collectively, our results provide compelling evidence that in the LrPduO active site, the corrin ring of Co(II)rrinoids is firmly locked in place by several amino acid side chains so as to facilitate the dissociation of the axial ligand.

Modulation of the gut microbiome: a systematic review of the effect of bariatric surgery

“…Lactobacillus can play a role by producing lactic acid and extracting energy from the fermentation of different sugars, which helps regulate the corpulence metabolism in people with obesity (50). Because bariatric surgery delays glucose and amino absorption in the host tract, the increase in simple sugars and amino acids in the large intestine may activate the colonic bacteria to derive energy from malabsorbed nutrients (51,52,53). Although C. comes has been found to be correlated with the inflammation procedure and bile acid homeostasis, the mechanism that affects the host metabolism remains unclear, which suggests more investigations (54,55,56).…”

Vibronic Coupling in Vitamin B12: A Combined Spectroscopic and Computational Study

“…7,13 rR spectroscopy has been employed, for example, to assess the extent of corrin ring perturbations imposed on Co II cobalamin (Co II Cbl) by the adenosyltransferase PduO. 14 The binding of Co II Cbl to PduO in the presence of co-substrate ATP was found to affect both the frequencies and relative intensities of corrin stretching modes. Through a combination of spectroscopic and computational methods, it was demonstrated that these changes arise from the tight binding imposed by PduO to prevent repositioning of its Co II Cbl substrate.…”

“…Previous computational analyses of the vibrational spectra of cobalamins have either neglected resonance enhancement of vibrational modes 39−42 or considered the relative resonance enhancement of only a select number of corrin stretching modes. 12,14 In this paper, we present a detailed analysis of rR spectra and vibronic coupling in CNCbl as predicted by the B3LYP and BP86 functionals. We used these data to guide further rR spectroscopic studies and identified, for the first time, isotope-sensitive features that can be attributed to the Co−C stretching and Co−C−N bending modes of CNCbl.…”

“…rR spectra of Cbl species are thus dominated by corrin-centered stretching modes in the high-frequency region (∼1500–1625 cm –1 ). These modes are sensitive to geometric parameters like corrin ring folding as well as to the Co oxidation state and the identity of axial ligands, all of which impact the extent to which the Co 3d valence orbitals mix with the corrin frontier orbitals. , rR spectroscopy has been employed, for example, to assess the extent of corrin ring perturbations imposed on Co II cobalamin (Co II Cbl) by the adenosyltransferase PduO . The binding of Co II Cbl to PduO in the presence of co-substrate ATP was found to affect both the frequencies and relative intensities of corrin stretching modes.…”

Resonance Raman Optical Activity Spectroscopy in Probing Structural Changes Invisible to Circular Dichroism Spectroscopy: A Study on Truncated Vitamin B12 Derivatives

“…Until now, vitamin B 12 and its derivatives have been extensively investigated by means of various methods including electronic absorption (UV-Vis) [ 23 , 24 , 25 , 26 ] as well as Raman spectroscopy techniques [ 27 , 28 , 29 , 30 , 31 , 32 ]. These methods supported by a theoretical approach guarantee insight into the complex nature and electronic or vibrational properties of corrinoids.…”