Science | James Sandy

James Sandy
Macromolecular Crystallography

James Sandy James Sandy is a support scientist with the Macromolecular Crystallography (MX) beamline I02. Before joining Diamond he spent nine years working in the Pharmacology Department at the University of Oxford. This time was spent investigating the structural aspects of the arylamine N-acetyltransferase (NAT) family of enzymes from prokaryotes, including protein:drug interactions. Most recently he determined a structure of a mycobacterial NAT enzyme in the presence of the anti-tubercular drug Isoniazid, which is inactivated by this family of enzymes.

Email: James Sandy
Tel: +44 (0) 1235 778555
MX Beamlines 

Key Research Areas

Macromolecular Crystallography, Protein:Ligand Interactions

Current Research Interests

Since antibiotics were first used in the 20th century, millions of people have benefited from available treatments. Unfortunately, the bacteria responsible for many diseases have developed resistance to the front-line treatments currently used. With the increase in multi-drug resistant strains of bacteria appearing worldwide there is a great need for the production of novel antibiotics. In addition, new anti-cancer drugs are required. Cancer is a leading cause of death worldwide, and these deaths are projected to continue rising, with an estimated 9 million people dying from cancer in 2015, rising to 11.4 million in 2030 (WHO Cancer factsheet). There are many strategies employed towards identifying new drugs. My research specifically deals with one pathway and the enzymes involved.

Amide Synthase Enzymes

The amide synthase enzymes are found in many species of bacteria. The gene encoding this enzyme is found at the end of a gene cluster encoding the polyketide synthase (PKS) enzymes. The amide synthase enzyme is responsible for a ring-closure reaction resulting in a large macrocyclic compound. These macrocyclic compounds have antibiotic or anti-tumour properties.

Actinosynemma pretiosum bacteria produce the anti-tumour agent, ansamitocin. The amide synthase enzyme is responsible for a final stage of the drug’s synthesis and performs a ring-closure reaction yielding an amide-bond as shown below (dotted box).

James sandy diagram1
The amide synthase enzymes share high sequence similarity with the arylamine N-acetyltransferase (NAT) family of enzymes which are well characterised both biochemically and structurally, however, there is no structural information for the amide synthase enzymes. The gene cluster containing the amide synthase is also well characterised and produces polyketide synthase (PKS) enzymes.

The PKS system comprises many enzymes which build up the substrate in a step-wise manner. Novel antibiotics and anti-tumour agents could be produced by combining different enzymes from other organisms utilising the PKS system. The specific interactions provided by each enzyme have not been identified and characterised. There are many families of bacteria producing antibiotics or other drugs from which genes of interest could be taken to engineer novel PKS systems with differing activities. There is therefore an interest in knowing the structures of these enzymes in order to understand the mechanisms of drug biosynthesis.

james sandy diagram
The arylamine N-acetyltransferase enzyme from Mycobacterium smegmatis. The anti-tubercular agent Isoniazid can be seen bound in the active site.

Selected Publications

  1. "Structure of arylamine N-acetyltransferase reveals a catalytic triad." J. Sinclair, J. Sandy, R. Delgoda, E. Sim and M.E. Noble. (2000) Nature Structural Biology 7(7): 560-564
  2. "The Structure of Arylamine N-acetyltransferase from Mycobacterium smegmatis—An Enzyme which Inactivates the Anti-tubercular Drug, Isoniazid." J. Sandy, A. Mushtaq, A. Kawamura, J. Sinclair, E. Sim and M.E. Noble. (2002) Journal of Molecular Biology 318: 1071-1083
  3. "Structural investigation of mutant Mycobacterium smegmatis arylamine N-acetyltransferase: a model for a naturally occurring functional polymorphism in Mycobacterium tuberculosis arylamine N-acetyltransferase". A. Kawamura, J. Sandy, A. Upton, M.E. Noble and E. Sim. (2003) Protein Expression and Purification 27: 75-84
  4. "Binding of the anti-tubercular drug isoniazid to the arylamine N-acetyltransferase protein from Mycobacterium smegmatis." J. Sandy, S.J. Holton, E. Fullam, E. Sim and M.E. Noble. (2005) Protein Science 14: 775-782
  5. "Investigation of the catalytic triad of arylamine N-acetyltransferases: essential residues required for acetyl transfer to arylamines." J. Sandy, A. Mushtaq, S.J. Holton, P. Schartau, M.E. Noble and E. Sim. (2005) Biochemical Journal 390:115-123