Table 4.
Predicted B-ZIP Dimerization Partners
| Sum and attractive and repulsive interactions | Protein | B-ZIP family | Predicted dimerization partners (# attractive interactions) | Comments |
| +3 | CG7786 | PAR | Homo (6) CREB (5) | Mammalian PAR proteins homodimerize and heterodimerize within the family; in contrast,Drosophila PAR proteins are predicted to homodimerize. |
| +3 | CG17888 (Pdp1) | PAR | Homo (6) | N in the 4th heptad “a” position will inhibit heterodimerization with other PAR proteins. |
| +3 | CG3136 | ATF6 | Homo (6) | N in the 3rd heptad “a” position will inhibit heterodimerization with other PAR proteins. |
| +2 | CG4575 | PAR | Homo (4) | Reversal of the 3rd heptad salt bridge from E ↔ R to R ↔ E will inhibit heterodimerization with other PAR proteins. |
| +2 | Creb | CREB | Homo (4) Giant (3) | Short zipper and attractive 1st and 3rd g ↔ e′ interactions characteristic of mammalian CREB.Presence of three Q's in the “g” positions of giant may stabilize a CREB/giant heterodimer. |
| +2 | CG8669 | ATF4 | 18619 (4) Sis A (−2) | Charged interface with an E in the 1st heptad “a” position and an R in the 3rd heptad “d” position. May heterodimerize via a salt bridge in the hydrophobic interior with CG18619, an R in the 3rd “d” position with an E in the 3rd “a” position of SisA. An interaction with SisA has been observed in a yeast interaction screen (Jim Erickson, unpublished observations). |
| +2 | CrebA | Oasis | Homo (4) | An N in the 4th heptad “a” position is predicted to promote homodimerization and prevent heterodimerization. |
| +2 | CG12850 | ??? | Homo (4) | Three polar “a” and “d” positions are predicted to cause homodimerization. |
| +2 | CG9954 | S-MAF | Homo (4) CG10034 (MAF) | Presence of an aliphatic rather than N in the 2ndheptad “a” position may allow heterodimerization with CG10034, which also has an aliphatic in the 2nd “a” position. Lysine in the 1st heptad “a” position and N in the 3rd heptad “a” position may cause other homodimerization. |
| +1 | Giant | PAR | Homo (2) CG7786 (2) or CREB (3) | |
| +1 | Slbo | C/EBP | A3-3 (2) | Resembles mammalian fos in having lysine in the 2nd “a” position. Two incomplete g ↔ e′ interactions in the 1st and 2nd heptads give the potential for promiscuous dimerization. |
| +1 | CG10034 | L-MAF | MAF (2) | Atypical interface with an L and R in the 2nd and 4th“a” positions, respectively. Predicted to heterodimerize with MAF, which also has L in the 2nd “a” position. |
| +1 | CG13624 | ?? | 4th heptad “d” position K may drive heterodimerization. | |
| +1 | Vri | C/EBP | Homo (2) A3-3 (2); cnc (0) or kay (3) | Has canonical hydrophobic interface with three incomplete g ↔ e′ interactions that are all basic, suggesting heterodimerization with any of the acidic zippers (A3-3, cnc, kay). |
| 0 | CG9415 | ATF6 | Homo (6) | Polar residues in the “a” positions of the 2nd, 4th, and 5th heptads that may drive homodimerization. Attractive interactions in the 5th, 6th, and 7th heptads will also encourage homodimerization. |
| 0 | SisA | ATF4 (1) | The R in the 2nd “a” position and E in the 3rd “a” position is likely to prevent homodimerization. ATF4 is one possible partner. | |
| −1 | Jra | JUN | A3-3 (4); cnc (3); kay (4) | Canonical interface. Presence of a basic repulsive pair in heptad 1 and partial g ↔ e′ interactions in heptads 2–4 indicate likely heterodimerization with acid zipper proteins that can form g ↔ e′ pairs. |
| −1 | CG6272 | C/EBP | A3-3 (4); cnc (3); kay (0) | Like Jra, has a repulsive basic pair in heptad 1, suggesting acidic zipper dimerization partners. Charged residues in “e” positions may promote promiscuous heterodimerization. |
| −1 | Cnc | CNC | Jra (3) CG6272 (1) | Acidic zippers predicted to interact with basic zippers Jra and C6272. |
| −2 | Kay | FOS | Jra (4) | Repulsive interaction in the 1st interaction and a histidine in the 5th“d” position, as seen in mammalian FOS. Salt bridge pattern indicates likely heterodimerization. Kay has been biochemically purified as a heterodimer with Jra. |
