Recombinant Bdellovibrio bacteriovorus Glycine dehydrogenase [decarboxylating] (gcvP), partial

Introduction

The glycine cleavage system (GCS), also known as glycine decarboxylase complex or GDC, is a series of enzymes triggered by high concentrations of the amino acid glycine . Glycine dehydrogenase (decarboxylating), or glycine decarboxylase, is a component of the glycine cleavage system . The P protein, also known as glycine dehydrogenase (decarboxylating), is part of the glycine decarboxylase multienzyme complex (GDC) .

This article aims to provide a detailed overview of recombinant Bdellovibrio bacteriovorus Glycine dehydrogenase [decarboxylating] (GcvP), partial, including its function, characteristics, and significance.

Glycine Cleavage System

The glycine cleavage system (GCS) is a multienzyme complex that catalyzes the degradation of glycine . It is composed of four proteins: T-protein, P-protein, H-protein and L-protein. These proteins do not form a stable complex, making it more appropriate to refer to it as a system .

Components of the Glycine Cleavage System :

The glycine cleavage system catalyzes a reversible reaction in plants, animals, and bacteria :
$$
\text{Glycine} + \text{H}_4\text{folate} + \text{NAD}^+ \leftrightarrow 5,10\text{-methylene-H}_4\text{folate} + \text{CO}_2 + \text{NH}_3 + \text{NADH} + \text{H}^+
$$
The H-protein activates the P-protein, which catalyzes the decarboxylation of glycine and attaches the intermediate molecule to the H-protein to be shuttled to the T-protein . The H-protein then forms a complex with the T-protein, which uses tetrahydrofolate and yields ammonia and 5,10-methylenetetrahydrofolate. The glycine protein system is regenerated when the H-protein is oxidized to regenerate the disulfide bond in the active site by interaction with the L-protein, which reduces $$\text{NAD}^+$$ to NADH and $$\text{H}^+$$ .

Glycine Dehydrogenase (Decarboxylating)

Glycine dehydrogenase (decarboxylating) (EC 1.4.4.2) catalyzes the following chemical reaction :
$$
\text{glycine} + \text{H-protein-lipoyllysine} \leftrightarrow \text{H-protein-S-aminomethyldihydrolipoyllysine} + \text{CO}_2
$$
The enzyme employs pyridoxal phosphate as a cofactor and participates in glycine, serine, and threonine metabolism . Glycine decarboxylase is the P-protein of the glycine cleavage system in eukaryotes . The P protein binds the alpha-amino group of glycine through its pyridoxal phosphate cofactor . Carbon dioxide is released, and the remaining methylamine moiety is then transferred to the lipoamide cofactor of the H protein .

Bdellovibrio bacteriovorus and Glycine Dehydrogenase (Decarboxylating)

Bdellovibrio bacteriovorus is a predatory bacterium known for invading and replicating within other Gram-negative bacteria . The role of glycine dehydrogenase (decarboxylating) in Bdellovibrio bacteriovorus is not well-documented.

Recombinant Glycine Dehydrogenase (Decarboxylating)

Recombinant glycine dehydrogenase (decarboxylating) refers to the enzyme produced through recombinant DNA technology . This involves introducing the gene encoding glycine dehydrogenase (decarboxylating) from Bdellovibrio bacteriovorus into a host organism (e.g., E. coli) for expression and production . The recombinant form of the enzyme can then be isolated and used for research purposes, such as studying its structure, function, and potential applications .

Clinical Significance

Defects in GLDC or AMT of the glycine cleavage system can lead to Glycine encephalopathy . Glycine encephalopathy is a primary disorder of the glycine cleavage system, resulting from lowered function and causing increased levels of glycine in body fluids .