Properties of an unusual heme cofactor in PLP-dependent cystathionine β-synthase

Singh, Siddharth; Madzelan, Peter; Banerjee, Ruma

doi:10.1039/b604182p

Cited by 74 publications

(51 citation statements)

References 65 publications

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“…The heme in CBS is a sixcoordinate, low spin protoporphyrin IX with cysteine and histidine residues serving as endogenous axial ligands. This heme is believed to have a regulatory function and inhibits CBS activity upon binding CO in the ferrous state or by undergoing a redox-dependent ligand switch (3,4,13,35,62,69,70,79). Binding of CO in ferrous CBS perturbs the heme environment and this is communicated to the PLP active site, resulting in a shift in the tautomeric equilibrium of PLP from the active ketoenamine to the inactive enolimine state (35,79).…”

Section: Overview Of H 2 S Metabolism In Humansmentioning

confidence: 99%

“…Although the mechanism by which H 2 S reduces the heme center in cytochrome c is unclear, it has been suggested that sulfide can bind and reduce the heme iron thus affecting the redox state of the protein (28,55). Interestingly, the heme in CBS, the hemeprotein that catalyzes H 2 S biosynthesis, also has a cysteine ligand at the distal site and a histidine at the proximal site (69,70). Thus, the interaction of H 2 S with CBS and cytochrome c warrants further investigations.…”

Section: Role Of H 2 S Reactivity With Hemeproteins: Concluding Commementioning

confidence: 99%

See 1 more Smart Citation

Hydrogen Sulfide and Hemeproteins: Knowledge and Mysteries

Pietri

Román-Morales

López‐Garriga

2011

Antioxidants & Redox Signaling

190

136

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Historically, hydrogen sulfide (H(2)S) has been regarded as a poisonous gas, with a wide spectrum of toxic effects. However, like ·NO and CO, H(2)S is now referred to as a signaling gas involved in numerous physiological processes. The list of reports highlighting the physiological effects of H(2)S is rapidly expanding and several drug candidates are now being developed. As with ·NO and CO, not a single H(2)S target responsible for all the biological effects has been found till now. Nevertheless, it has been suggested that H(2)S can bind to hemeproteins, inducing different responses that can mediate its effects. For instance, the interaction of H(2)S with cytochrome c oxidase has been associated with the activation of the ATP-sensitive potassium channels, regulating muscle relaxation. Inhibition of cytochrome c oxidase by H(2)S has also been related to inducing a hibernation-like state. Although H(2)S might induce these effects by interacting with hemeproteins, the mechanisms underlying these interactions are obscure. Therefore, in this review we discuss the current state of knowledge about the interaction of H(2)S with vertebrate and invertebrate hemeproteins and postulate a generalized mechanism. Our goal is to stimulate further research aimed at evaluating plausible mechanisms that explain H(2)S reactivity with hemeproteins.

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Section: Overview Of H 2 S Metabolism In Humansmentioning

confidence: 99%

Section: Role Of H 2 S Reactivity With Hemeproteins: Concluding Commementioning

confidence: 99%

Hydrogen Sulfide and Hemeproteins: Knowledge and Mysteries

Pietri

Román-Morales

López‐Garriga

2011

Antioxidants & Redox Signaling

190

136

View full text Add to dashboard Cite

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“…1) (reviewed in Refs. [2][3][4]. The enzyme contains four identical subunits each having three domains: an N-terminal domain, which binds heme cofactor of unclear function; a highly conserved catalytic core with pyridoxal-5Ј-phosphate (PLP) cofactor; and a C-terminal regulatory domain, which contains the CBS domain tandem and binds S-adenosyl-L-methionine (AdoMet).…”

mentioning

confidence: 99%

“…Missense mutations account for ϳ87% of all mutations in CBSDH, 4 the most common disorder of sulfur amino acids metabolism (1). Many of these mutations do not target the catalytic residues in CBS but rather result in misfolded proteins, which lack biological function and/or are destined for degradation.…”

mentioning

confidence: 99%

Rescue of Cystathionine β-Synthase (CBS) Mutants with Chemical Chaperones

Majtán

Liu

Carpenter

et al. 2010

Journal of Biological Chemistry

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Missense mutations represent the most common cause of many genetic diseases including cystathionine ␤-synthase (CBS) deficiency. Many of these mutations result in misfolded proteins, which lack biological function. The presence of chemical chaperones can sometimes alleviate or even restore protein folding and activity of mutant proteins. We present the purification and characterization of eight CBS mutants expressed in the presence of chemical chaperones such as ethanol, dimethyl sulfoxide, or trimethylamine-N-oxide. Preliminary screening in Escherichia coli crude extracts showed that their presence during protein expression had a significant impact on the amount of recovered CBS protein, formation of tetramers, and catalytic activity. Subsequently, we purified eight CBS mutants to homogeneity (P49L, P78R, A114V, R125Q, E176K, P422L, I435T, and S466L). The tetrameric mutant enzymes fully saturated with heme had the same or higher specific activities than wild type CBS. Thermal stability measurements demonstrated that the purified mutants are equally or more thermostable than wild type CBS. The response to S-adenosyl-Lmethionine stimulation or thermal activation varied. The lack of response of R125Q and E176K to both stimuli indicated that their specific conformations were unable to reach the activated state. Increased levels of molecular chaperones in crude extracts, particularly DnaJ, indicated a rather indirect effect of the chemical chaperones on folding of CBS mutants. In conclusion, the chemical chaperones present in the expression medium were able to fully restore the activity of eight CBS mutants by improving their protein folding. This finding could have direct implications for the development of a therapeutical approach to pyridoxine unresponsive homocystinuria.

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“…2). In higher eukaryotes, such as insects, rodents and mammals (Meier et al, 2001;Koutmos et al, 2010), the N-terminal region includes a haembinding domain that is thought to function in redox sensing and/or enzyme folding (Janosík, Oliveriusová et al, 2001;Singh et al, 2007;Majtan et al, 2010). This region is absent in CBS enzymes from lower eukaryotes, such as Saccharomyces cerevisiae, Trypanosoma cruzi and Caenorhabditis elegans (Jhee et al, 2000;Maclean et al, 2000;Nozaki et al, 2001;Vozdek et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Purification, crystallization and preliminary crystallographic analysis of the catalytic core of cystathionine β-synthase fromSaccharomyces cerevisiae

et al. 2014

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Cystathionine β‐synthase (CBS; EC 4.2.1.22) catalyzes the condensation of homocysteine and serine to form cystathionine, with the release of water. In humans, deficiency in CBS activity is the most common cause of hyperhomocysteinaemia and homocystinuria. More than 160 pathogenic mutations in the human CBS gene have been described to date. Here, the purification and preliminary crystallographic analysis of the catalytic core of CBS from Saccharomyces cerevisiae (ScCBS) is described which, in contrast to other eukaryotic CBSs, lacks the N‐terminal haem‐binding domain and is considered to be a useful model for investigation of the pyridoxal‐5′‐phosphate‐mediated reactions of human CBS (hCBS). The purified protein yielded two different crystal forms belonging to space groups P41212 and P212121, with unit‐cell parameters a = b = 72.390, c = 386.794 Å and a = 58.156, b = 89.988, c = 121.687 Å, respectively. Diffraction data were collected to 2.7 and 3.1 Å resolution, respectively, using synchrotron radiation. Preliminary analysis of the X‐ray data suggests the presence of ScCBS homodimers in both types of crystals.

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Properties of an unusual heme cofactor in PLP-dependent cystathionine β-synthase

Cited by 74 publications

References 65 publications

Hydrogen Sulfide and Hemeproteins: Knowledge and Mysteries

Hydrogen Sulfide and Hemeproteins: Knowledge and Mysteries

Rescue of Cystathionine β-Synthase (CBS) Mutants with Chemical Chaperones

Purification, crystallization and preliminary crystallographic analysis of the catalytic core of cystathionine β-synthase fromSaccharomyces cerevisiae

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