This icon signals the start of the many discussions that highlight protein commonalities or other molecular evolutionary insights.

Only l amino acids make up proteins

Why this set of 20 amino acids?

Sickle-cell trait and malaria

Additional human globin genes

Catalytic triads in hydrolytic enzymes

Major classes of peptide-cleaving enzymes

Common catalytic core in type II restriction enzymes

P-loop NTPase domains

Conserved catalytic core in protein kinases

Why do different human blood types exist?

Archaeal membranes

Ion pumps

P-type ATPases

ATP-binding cassettes

Sequence comparisons of Na⁺ and Ca²⁺ channels

Small G proteins

Metabolism in the RNA world

Why is glucose a prominent fuel?

NAD⁺ binding sites in dehydrogenases

Isozymic forms of lactate dehydrogenase

Evolution of glycolysis and gluconeogenesis

The α-ketoglutarate dehydrogenase complex

Domains of succinyl CoA synthetase

Evolution of the citric acid cycle

Mitochondrial evolution

Conserved structure of cytochrome c

Common features of ATP synthase and G proteins

Pigs lack uncoupling protein 1 (UCP-1) and brown fat

Related uncoupling proteins

Chloroplast evolution

Evolutionary origins of photosynthesis

Evolution of the C4 pathway

The relationship of the Calvin cycle and the pentose phosphate pathway

Increasing sophistication of glycogen phosphorylase regulation

Glycogen synthase is homologous to glycogen phosphorylase

A recurring motif in the activation of carboxyl groups

Prokaryotic counterparts of the ubiquitin pathway and the proteasome

A family of pyridoxal-dependent enzymes

Evolution of the urea cycle

The P-loop NTPase domain in nitrogenase

Conserved amino acids in transaminases determine amino acid chirality

Feedback inhibition

Recurring steps in purine ring synthesis

Ribonucleotide reductases

Increase in urate levels during primate evolution

Deinococcus radiodurans illustrates the power of DNA repair systems

DNA polymerases

Thymine and the fidelity of the genetic message

Sigma factors in bacterial transcription

Similarities in transcription between archaea and eukaryotes

Evolution of spliceosome-catalyzed splicing

Classes of aminoacyl-tRNA synthetases

Composition of the primordial ribosome

Homologous G proteins

A family of proteins with common ligand-binding domains

The independent evolution of DNA-binding sites of regulatory proteins

Key principles of gene regulation are similar in bacteria and archaea

CpG islands

Iron-response elements

miRNAs in gene evolution

The odorant-receptor family

Photoreceptor evolution

The immunoglobulin fold

Relationship of tubulin to prokaryotic proteins

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