Fig. 5. (A) Alignment of the four subdomains within the N-terminal half of XMAP215, labeled N1-N4 and identified specifically on the last line. Amino acids conserved in three or four of the subdomains are indicated above the alignment. The HEAT repeats identified in TOGp by Neuwald and Hirano (Neuwald and Hirano, 2000) are shown in red (we transferred the repeats from TOGp to the closely related XMAP215 sequence). This alignment shows four segments where three subdomains have HEAT repeats, suggesting that the fourth subdomain also has one, not identified by the sequence analysis. A sixth HEAT repeat may occur in the final part of each subdomain, but this is not recognizable from the sequence. (B) A diagram of the TOGp sequence showing the location of HEAT repeats as dark boxes. The positions are nearly identical in XMAP215. A 36 amino acid insert in XMAP215 (Becker and Gard, 2000) is located N-terminal to the last four identified repeats. The other XMAP215 insert is located C-terminal to the identified HEAT repeats. The dark boxes below indicate HEAT repeats identified by Neuwald and Hirano (Neuwald and Hirano, 2000), and the open boxes indicate additional repeats suggested by the alignment in A. The sub-domains N1-N4 are indicated above.