1C96

S642A:CITRATE COMPLEX OF ACONITASE

Summary for 1C96

• Entry DOI: 10.2210/pdb1c96/pdb
• Related: 1C97
• Descriptor: MITOCHONDRIAL ACONITASE, CITRATE ANION, IRON/SULFUR CLUSTER, ... (5 entities in total)
• Functional Keywords: lyase, tricarboxylic acid cycle, iron-sulfur, mitochondrion, transit peptide, 4fe-4s
• Biological source: Bos taurus (cattle)
• Total number of polymer chains: 1
• Total formula weight: 83174.68

Authors

Lloyd, S.J.,Lauble, H.,Prasad, G.S.,Stout, C.D. (deposition date: 1999-07-31, release date: 1999-08-12, Last modification date: 2024-02-07)

Primary citation

Lloyd, S.J.,Lauble, H.,Prasad, G.S.,Stout, C.D.
The mechanism of aconitase: 1.8 A resolution crystal structure of the S642a:citrate complex.
Protein Sci., 8:2655-2662, 1999

PubMed Abstract: The crystal structure of the S642A mutant of mitochondrial aconitase (mAc) with citrate bound has been determined at 1.8 A resolution and 100 K to capture this binding mode of substrates to the native enzyme. The 2.0 A resolution, 100 K crystal structure of the S642A mutant with isocitrate binding provides a control, showing that the Ser --> Ala replacement does not alter the binding of substrates in the active site. The aconitase mechanism requires that the intermediate product, cis-aconitate, flip over by 180 degrees about the C alpha-C beta double bond. Only one of these two alternative modes of binding, that of the isocitrate mode, has been previously visualized. Now, however, the structure revealing the citrate mode of binding provides direct support for the proposed enzyme mechanism.

PubMed: 10631981

Experimental method

X-RAY DIFFRACTION (1.81 Å)