Spermine synthase.
Spermine is present in many organisms including animals, plants, some fungi, some archaea, and some bacteria. It is synthesized by spermine synthase, a highly specific aminopropyltransferase. This review describes spermine synthase structure, genetics, and function. Structural and biochemical studies reveal that human spermine synthase is an obligate dimer. Each monomer contains a C-terminal domain where the active site is located, a central linking domain that also forms the lid of the catalytic domain, and an N-terminal domain that is structurally very similar to S-adenosylmethionine decarboxylase. Gyro mice, which have an X-chromosomal deletion including the spermine synthase (SMS) gene, lack all spermine and have a greatly reduced size, sterility, deafness, neurological abnormalities, and a tendency to sudden death. Mutations in the human SMS lead to a rise in spermidine and reduction of spermine causing Snyder-Robinson syndrome, an X-linked recessive condition characterized by mental retardation, skeletal defects, hypotonia, and movement disorders.
Department of Cellular and Molecular Physiology, Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA. aep1@psu.edu
Anthony E
AE
Pegg
Anthony J
AJ
Michael
D000818:Animals; D041321:Chromosomes, Human, X; D006801:Humans; D051379:Mice; D013095:Spermidine / Q000378:metabolism; D013096:Spermine / Q000378:metabolism; D013097:Spermine Synthase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D013096:Spermine; D013097:Spermine Synthase; D013095:Spermidine