Creatine kinase structure

Kenyon, G.L. Reed, G.H. Creatine kinase structure-activity relationships. Adv. Enzymol. Relat. Areas Mol. Biol., 54, 367-426 (1983)... 

Wallimann, T., Wyss. M., Brdicza, D., Nicolay, K.. Eppenberger, H.M. (1992). Intracellular compartmentation. structure and function of creatine kinase isoenzymes in tissues with high and fluctuating energy demands The phosphocreatine circuit for cellular energy homeostasis. Biochem. J. 281,21-40. 

The second mode of toxicity is postulated to involve the direct interaction of the epidithiodiketopiperazine motif with target proteins, forming mixed disulfides with cysteine residues in various proteins. Gliotoxin, for example, has been demonstrated to form a 1 1 covalent complex with alcohol dehydrogenase [13b, 17]. Epidithiodi-ketopiperazines can also catalyze the formation of disulfide bonds between proxi-mally located cysteine residues in proteins such as in creatine kinase [18]. Recently, epidithiodiketopiperazines have also been implicated in a zinc ejection mechanism, whereby the epidisulfide can shuffle disulfide bonds in the CHI domain of proteins, coordinate to the zinc atoms that are essential to the tertiary structure of that domain, and remove the metal cation [12d, 19],... 

The enzyme responsible for this topping-up ATP in active muscle is CK. CK is found in high concentration in muscle cells, both free within the sarcoplasm and also associated with membranes of mitochondria and the sarcoplasmic reticulum. Structurally, creatine kinase is a dimeric enzyme of B and/or M subunits, each of about 40 kDa. Three quaternary structure isoenzyme forms arise CK-MM, CK-BB and CK-MB. The predominant form in all muscles is CK-MM, but cardiac muscle also contains a significant amount of CK-MB and this isoenzyme can be used as a specific marker of myocardial damage (see Case Notes at the end of this chapter). 

General aspects of enzymatic reactions cateuLyzed by kinases are briefly mentioned. Many alternate substrates, competitive inhibitors and affinity labels based either on the structure of ATP or on the structure of the non-ATP kinase substrates are described. Several examples are presented that should be of particular interest to the medicinal chemist. Finally, the design of an affinity label for creatine kinase is reviewed as an example of how such information can be used in the search for agents directed at an enzyme s active site. 

Designing specific enzyme inhibitors on a rational basis when one does not have a detailed three-dimensional crystal structure to which to relate is a rather sophisticated challenge. Some viable approaches to such a challenge are discussed in a review chapter by Santi and Kenyon (91) This discussion will focus on our rationale for the design of an affinity label for creatine kinase, namely N-(2,3-epoxypropyl)-N-amidinoglycine (epoxycreatine ) ... 

Exploration of Bulk Tolerance. Most affinity labels contain functional groups added to the substrate s basic structure. Discerning just where added bulk can be tolerated by the enzyme is therefore crucial information. In the case of creatine, it has been determined (92,93) that the structures below, for example, are good substitutes for creatine in the creatine-kinase reaction... 

Figure 4.. Possible structure of the transition state for phos-phoryl transfer in the creatine kinase reaction. Adapted from Cook et al(95).

Schlegel, J. Zurbriggen, B. Wegmann, G. Wyss, M. Eppenberger, H.M. Wallimann, T. Native mitochondrial creatine kinase forms octameric structures. I. Isolation of two interconvertible mitochondrial creatine kinase forms, dimeric and octameric mitochondrial creatine kinase characterization, localization, and structure-function relationships. J. Biol. Chem., 263, 16942-16953 (1988)... 

Madelian, V. Warren, W.A. Properties of a structurally and functionally altered form of creatine kinase produced in solutions containing chloride and nitrate. Arch. Biochem. Biophys., 184, 103-110 (1977)... 

Schlattner, U. Eder, M. Bolder, M. Khuchua, Z.A. Strauss, A.W. Walli-mann, T. Divergent enzyme kinetics and structural properties of the two human mitochondrial creatine kinase isoenzymes. Biol. Chem., 381, 1063-1070 (2000)... 

K.N. The 2.1 A structure of Torpedo californica creatine kinase complexed with the ADP-Mg -NOj-creatine transition-state analogue complex. Biochemistry, 41, 13861-13867 (2002)... 

Eder, M. Fritz-Wolf, K. Kabsch, W. Wallimann, T. Schlattner, U. Crystal structure of human ubiquitous mitochondrial creatine kinase. Proteins, 39, 216-225 (2000)... 

K. Crystal structure of brain-type creatine kinase at 1.41 A resolution. Protein Sci., 8, 2258-2269 (1999)... 

Rao, J.K. Bujacz, G. Wlodawer, A. Crystal structure of rabbit muscle creatine kinase. FEBS Lett., 439, 133-137 (1998)... 

Quaternary structure of isoenzymes Many isoenzymes contain different subunits in various combinations. For example, creatine kinase occurs as three isoenzymes. Each isoenzyme is a dimer composed of two polypeptides (called B and M subunits) associated in one of three combinations CK1 = BB, CK2 = MB, and CK3 - MM. Each CK isoenzyme shows a characteristic electrophoretic mobility (see Figure 5.21). 

Subunit structure and electrophoretic mobility and enzyme activity of creatine kinase isoenzymes. 

Figure 12-19 Proposed transition state structure formed from Mn2+i ATP, and creatine bound in the active site of muscle creatine kinase. Based on EPR spectroscopy with regiospecifically 170-labeled substrates. The electrical charges have been added in one possible constellation. However, hydrogen atoms bound to phospho groups are not shown. After Leyh et al.68i...

Creatine kinase sequences are known for many different species and iso-forms, so species-specificity of MAbs can often be used for refining the details of epitope mapping. Natural variants that prevent MAb binding are likely to involve contact residues, because the overall protein structures (and enzyme activity) are likely to be retained. The CK-2A7 MAb in Fig. IB binds between Met-29 and Cys-73. It recognizes rabbit and Torpedo CKs, as well as chick CK, but it fails to bind to either rat muscle CK or rabbit brain CK. This suggests that Lys-39 is required for CK-2A7 binding, since it is replaced by Asn m rat muscle CK and by Ala in rabbit brain CK (7), and is the only amino acid change consistent with the observed CK-2A7 specificity. 

Nguyen thi Man, Cartwright, A J., Osborne, M., and Morris, G E (1991) Structural changes in the C-terminal region of human brain creatine kinase studied with monoclonal antibodies Biochim Biophys. Acta 1076, 245-251. 

Adenosine triphosphate creatine A-phosphotransferase (EC 2.7.3.2), also creatine phosphokinase. Creatine kinase is found in muscle and is responsible for the formation of creatine phosphate from creatine and adenosine triphosphate creatine phosphate is a higher energy source for muscle contraction. Creatine kinase is elevated in all forms of muscular dystrophy. Creatine kinase is dimer and is present as isozymes (CK-1, BB CK-2, MB CK-3, MM) and Ck-mt (mitochondrial). Creatine kinase is also used to measure cardiac muscle damage in myocardial infarction. See Bais, R. and Edwards, J.B., Creatine kinase, CRC Crit. Rev. Clin. Lab. ScL 16, 291-355, 1982 McLeish, M.J. and Kenyon, G.L., Relating structure to mechanism in creatine kinase, Crit. Rev. Biochem. Mol. Biol 40, 1-20, 2005. 

Figure 31.20. Enhancer Binding Sites. A schematic structure for the region 1 kb upstream of the start site for the muscle creatine kinase gene. One binding site of the form 5 -CAGCTG-3 is present near the TATA box. The enhancer region farther upstream contains two binding sites for the same protein and two additional binding sites for other proteins.

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