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Croatian Association of Crystallographers ***** Bijenička c. 54 HR-10000 Zagreb Croatia
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Triumph over Adversity: the structure determination of TBNAT
Elspeth Garman, Department of Biochemistry, University of Oxford, Oxford, UK.
This
talk will relate the history and outcome of a (very) challenging case for
protein crystallography structure determination: that of Arylamine N-acetyltransferase
from Mycobacterium tuberculosis (TBNAT). This enzyme plays an important
role in the intracellular survival of the microorganism inside macrophages.
Medicinal chemistry efforts to optimize inhibitors of the TBNAT enzyme have been
hampered by the lack of a three-dimensional structure of the enzyme. The
structure of TBNAT was determined using a lone 25
micron
crystal produced using cross seeding with the homologous protein (MMNAT) from
M. marinum, following extensive difficulties which had to be overcome during
expression, purification and crystallisation of the enzyme. Despite the
similarity between MMNAT and TBNAT (74% sequence identity), the enzymes show
distinct physical and biochemical characteristics. The TBNAT structure [1]
elegantly reveals the characteristic features of the protein surface as well as
details of the active site of TBNAT relevant to drug-discovery efforts. The
crystallographic analysis of the diffraction data presented many challenges,
since the crystal was twinned and the habit possessed pseudo-translational
symmetry: these will be described.
[1]
Areej Abuhammad, Edward D. Lowe, Michael A. McDonough, Patrick D. Shaw Stewart,
Stefan A. Kolek, Edith Sim and Elspeth F. Garman. Acta Cryst. (2013). D69,
1433–1446 |
The workshop is generously supported by:
Ministry of Science, Education and Sports of the Republic of Croatia International Union of Crystallography European Crystallographic Association
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