Biocrystallization

Biocrystallization is the formation of crystals from organic macromolecules by living organisms.^[1] This may be a stress response, a normal part of metabolism such as processes that dispose of waste compounds, or a pathology. Template mediated crystallization is qualitatively different from in vitro crystallization. Inhibitors of biocrystallization are of interest in drug design efforts against lithiasis and against pathogens that feed on blood, since many of these organisms use this process to safely dispose of heme.

DNA

Part of a series related to
Biomineralization
General Mineralized tissues Remineralisation Biocrystallization Biointerface Biofilm
Exoskeletons (shells) Arthropod exoskeleton cuticle Brachiopod shell Cephalopod shell cirrate shell cuttlebone gladius Lorica Choanoflagellate lorica Protist shell coccosphere coccolith diatom frustule foraminifera test testate amoebae Seashell echinoderm stereom mollusc shell nacre chiton shell gastropod shell small shelly fauna scaly-foot snail shell estuary shells Sponge spicule Test
Endoskeletons (bones) Vertebrate skeleton Bone mineral Ossification
Teeth, scales, tusks etc Limpet teeth Otolith otolithic membrane Scale microfossils Tusk
Calcification amorphous calcium carbonate marine biogenic calcification calcareous nannofossils Aragonite oolitic aragonite sand aragonite sea Calcite microbial calcite precipitation calcite sea Great Calcite Belt
Silicification biogenic silica siliceous ooze diatomaceous earth
Other forms Bone bed Kerogen alginite oil shale Phosphate phosphorite Pyrena
Related Mineral evolution In soil mineralization immobilization Ballast minerals Magnetofossil Magnetosome Magnetotactic bacteria Magnetoreception Microfossils engrailed gene Druse Cupriavidus metallidurans Biomineralising polychaetes Mineral nutrients Microbial mat Fossilization permineralization petrifaction Burgess Shale preservation
Category
v t e

Under severe stress conditions the bacteria Escherichia coli protects its DNA from damage by sequestering it within a crystalline structure.^[2] This process is mediated by the stress response protein Dps and allows the bacteria to survive varied assaults such as oxidative stress, heat shock, ultraviolet light, gamma radiation and extremes of pH.^[3][4]

Heme

Blood feeding organisms digest hemoglobin and release high quantities of free toxic heme. To avoid destruction by this molecule, the parasite biocrystallizes heme to form hemozoin.^[5] To date, the only definitively characterized product of hematin disposal is the pigment hemozoin. Hemozoin is per definitionem not a mineral and therefore not formed by biomineralization. Heme biocrystallization has been found in blood feeding organisms of great medical importance including Plasmodium, Rhodnius and Schistosoma. Heme biocrystallization is inhibited by quinoline antimalarials such as chloroquine.

Targeting heme biocrystallization remains one of the most promising avenues for antimalarial drug development because the drug target is highly specific to the malarial parasite, and outside the genetic control of the parasite.

Lithiasis

Lithiasis (formation of stones) is a global human health problem. Stones can form in both urinary and gastrointestinal tracts. Related to the formation of stones is the formation of crystals; this can occur in joints (e.g. gout) and in the viscera.^[6]

See also

References

External links

• Order in stress – Lessons from the inanimate world