PDBsum entry 1f9c

Isomerase

PDB id: 1f9c

Contents

Protein chains

360 a.a. *

Metals

_MN ×2

Waters ×195

* Residue conservation analysis

PDB id:

1f9c

Name:

Isomerase

Title:

Crystal structure of mle d178n variant

Structure:

Protein (muconate cycloisomerase i). Chain: a, b. Synonym: cis,cis-muconate lactonizing enzyme i, mle. Engineered: yes. Mutation: yes

Source:

Pseudomonas putida. Organism_taxid: 303. Strain: prs2000. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Octamer (from PDB file)

Resolution:

2.50Å R-factor: 0.187 R-free: 0.234

Authors:

T.Kajander,L.Lehtio,P.C.Kahn,A.Goldman

Key ref:

T.Kajander et al. (2000). Buried charged surface in proteins. Structure, 8, 1203-1214. PubMed id: 11080642 DOI: 10.1016/S0969-2126(00)00520-7

Date:

10-Jul-00 Release date: 07-Mar-01

Protein chains

Q51958  (Q51958_PSEPU) -  Muconate lactonizing enzyme from Pseudomonas putida

Seq: 373 a.a.

Struc: 360 a.a.*

* PDB and UniProt seqs differ at 4 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.5.5.1.1 - muconate cycloisomerase.
• Pathway: Benzoate Metabolism
• Reaction: (S)-muconolactone = cis,cis-muconate + H⁺
• Cofactor: Mn(2+)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Key reference

DOI no: 10.1016/S0969-2126(00)00520-7

Structure 8:1203-1214 (2000)

PubMed id: 11080642

Buried charged surface in proteins.

T.Kajander, P.C.Kahn, S.H.Passila, D.C.Cohen, L.Lehtiö, W.Adolfsen, J.Warwicker, U.Schell, A.Goldman.

ABSTRACT

BACKGROUND: The traditional picture of charged amino acids in globular proteins is that they are almost exclusively on the outside exposed to the solvent. Buried charges, when they do occur, are assumed to play an essential role in catalysis and ligand binding, or in stabilizing structure as, for instance, helix caps. RESULTS: By analyzing the amount and distribution of buried charged surface and charges in proteins over a broad range of protein sizes, we show that buried charge is much more common than is generally believed. We also show that the amount of buried charge rises with protein size in a manner which differs from other types of surfaces, especially aromatic and polar uncharged surfaces. In large proteins such as hemocyanin, 35% of all charges are greater than 75% buried. Furthermore, at all sizes few charged groups are fully exposed. As an experimental test, we show that replacement of the buried D178 of muconate lactonizing enzyme by N stabilizes the enzyme by 4.2 degrees C without any change in crystallographic structure. In addition, free energy calculations of stability support the experimental results. CONCLUSIONS: Nature may use charge burial to reduce protein stability; not all buried charges are fully stabilized by a prearranged protein environment. Consistent with this view, thermophilic proteins often have less buried charge. Modifying the amount of buried charge at carefully chosen sites may thus provide a general route for changing the thermophilicity or psychrophilicity of proteins.

Selected figure(s)

Figure 4.
Figure 4. The Structures of the Regions Containing D178, H181, and D150 in Wild-Type MLE and the D178N VariantWild type, (a); Di78N, (b). The path of the backbone is shown as a "worm." D178, H151, and D150, as well as residues that interact with them, are in ball and stick. Oxygen is red; nitrogen is blue. Hydrogen bonds are shown as dotted lines. The figure was prepared using MOLSCRIPT [65] and Raster3D [66]

The above figure is reprinted by permission from Cell Press: Structure (2000, 8, 1203-1214) copyright 2000.

Figure was selected by an automated process.