2a89

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spinqualitylabelsall models 2a89, resolution 1.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Monomeric Sarcosine Oxidase: Structure of a covalently flavinylated amine oxidizing enzyme

Overview

Monomeric sarcosine oxidase (MSOX) is a flavoprotein that contains, covalently bound FAD [8a-(S-cysteinyl)FAD] and catalyzes the oxidation of, sarcosine (N-methylglycine) and other secondary amino acids, such as, l-proline. Our previous studies showed that N-(cyclopropyl)glycine (CPG), acts as a mechanism-based inactivator of MSOX [Zhao, G., et al. (2000), Biochemistry 39, 14341-14347]. The reaction results in the formation of a, modified reduced flavin that can be further reduced and stabilized by, treatment with sodium borohydride. The borohydride-reduced CPG-modified, enzyme exhibits a mass increase of 63 +/- 2 Da as compared with native, MSOX. The crystal structure of the modified enzyme, solved at 1.85 A, resolution, shows that FAD is the only site of modification. The modified, FAD contains a fused five-membered ring, linking the C(4a) and N(5) atoms, of the flavin ring, with an additional oxygen atom bound to the carbon, atom attached to N(5) and a tetrahedral carbon atom at flavin C(4) with a, hydroxyl group attached to C(4). On the basis of the crystal structure of, the borohydride-stabilized adduct, we conclude that the labile, CPG-modified flavin is a 4a,5-dihydroflavin derivative with a substituent, derived from the cleavage of the cyclopropyl ring in CPG. The results are, consistent with CPG-mediated inactivation in a reaction initiated by, single electron transfer from the amine function in CPG to FAD in MSOX, followed by collapse of the radical pair to yield a covalently modified, 4a,5-dihydroflavin.

About this Structure

2A89 is a Single protein structure of sequence from Bacillus sp. with PO4, CL and FCG as ligands. Active as Sarcosine oxidase, with EC number 1.5.3.1 Full crystallographic information is available from OCA.

Reference

Structure of the sodium borohydride-reduced N-(cyclopropyl)glycine adduct of the flavoenzyme monomeric sarcosine oxidase., Chen ZW, Zhao G, Martinovic S, Jorns MS, Mathews FS, Biochemistry. 2005 Nov 29;44(47):15444-50. PMID:16300392

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