Structure of a halophilic nucleoside diphosphate kinase from Halobacterium salinarum.

Hüseyin Besir, Kornelius Zeth, Andreas Bracher, Ursula Heider, Matsujiro Ishibashi, Masao Tokunaga, Dieter Oesterhelt

Index: FEBS Lett. 579 , 6595-6600, (2005)

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Abstract

Nucleoside diphosphate kinase from the halophilic archaeon Halobacterium salinarum was crystallized in a free state and a substrate-bound form with CDP. The structures were solved to a resolution of 2.35 and 2.2A, respectively. Crystals with the apo-form were obtained with His6-tagged enzyme, whereas the untagged form was used for co-crystallization with the nucleotide. Crosslinking under different salt and pH conditions revealed a stronger oligomerization tendency for the tagged protein at low and high salt concentrations. The influence of the His6-tag on the halophilic nature of the enzyme is discussed on the basis of the observed structural properties.